Reverse Dictionary: SECRECY

ADJECTIVES
1000 • DERN of actions, etc.: done in secret or in the dark; kept concealed → obs.
………. • DERN of persons; secret in purpose or action; reserved → obs.
………. • DERN of places: secret, not generally known, private → arch.
………. • DIGHEL secret, obscure → obs.
1230 • PRIVY acting or carried out in secret or by stealth; clandestine → arch.
1275 • STILL secret → obs.
………. • STILLY secret → obs.
1303 • COVERT concealed, hidden, secret
1470 • SECRETIVE secret → obs.
1480 • OCCULT not disclosed or revealed; secret; kept secret
1484 • COVERED concealed, hidden, secret → obs.
1490 • FURTIVE done by stealth; clandestine, secret
………. • INTRINSIC secret, private → obs.
1500 • CLOAKED disguised, concealed, secret
1532 • DARK concealed; kept secret
1533 • QUIET acting or living quietly; remaining hid or secret; fast asleep → Sc. obs.
1548 • INWARD secret, private → obs.
1553 • LONG-TONGUED prone to revealing secrets or to speaking out of turn
1558 • PUDENT secret, hidden
1563 • CLANCULARY secret, private; clandestine, underhand → obs.
1547 • ARCANE hidden, concealed, secret
1565 • TITTLING spreading rumours secretly or quietly; tattling
1566 • CLANDESTINE secret, private, concealed
1576 • ABSTRUSE concealed, hidden, secret → obs.
1580 • ACROAMATICAL pert. to hearing; hence, privately communicated by oral teaching to chosen disciples only; esoteric, secret → obs.
1592 • CABINET private, confidential, secret 
………. • UNDERHAND secret, clandestine, surreptitious
1593 • LATENT disguised, secret
1598 • SINISTRAL secretive, underhand → obs.
………. • UNSHEWING secret → obs.
..17C • CLOSE AS OAK very retentive of secrets; secretive → colloq.
1600 • DERNED hidden, concealed, secret, privy → obs.
………. • MYSTICAL secret, concealed; unconfessed → obs.
1602 • LIP-SWORN having taken an oath of secrecy
………. • NET-DANCED done secretly or with the intention of secrecy → obs.
1616 • BLABBING that blabs or publishes secrets
1621 • CLANCULAR clandestine; secret; private; concealed → obs.
1625 • MYSTIC secret, concealed → obs.
1632 • ACROAMATIC pert. to hearing; hence, privately communicated by oral teaching to chosen disciples only; esoteric, secret
1638 • CRYPTIC secret, concealed, occult, mystical
1639 • PRODITORIOUS apt to reveal something hidden or secret, esp. a person’s innermost thoughts
1641 • SUBREPTITIOUS secret; clandestine
1643 • SUBTERRANEAN existing or working out of sight or secretly; clandestine, hidden
1645 • SURREPTITIOUS taken, done, etc. secretly or by stealth; secret and unauthorized; clandestine
1649 • CLOSETED secret, hidden; private, secluded
1650 • DARK of a person: secretive; silent as to any matter; reticent; that conceals his thoughts
1652 • ABSCONDED concealed, hidden away, secret → obs.
………. • SUBTERRANEOUS secret, clandestine
1653 • CRYPTOLOGICAL relating to secret communication; enigmatic, cryptic
1655 • ACROATIC pert. to hearing; hence, privately communicated by oral teaching to chosen disciples only; esoteric, secret
1656 • CLANCULARIOUS private, secret; unknown; clandestine, underhand → obs.
………. • OPERTANEOUS of secret, hidden, or covert nature; done in private, hidden from view, concealed → obs.
1673 • RECLUSE hidden, secret, private → obs.
1677 • UNDERGROUND hidden, concealed, secret
1692 • HUGGER-MUGGER secret, clandestine
1709 • SOPHIC obtained by some secret process → obs.
1710 • IN POIGNE secret, undisclosed → obs.
………. • SNUG marked by privacy, secrecy, or concealment; private, secret → obs.
1718 • FURTIVE taken by stealth or secretly
1720 • TITTLE-TATTLING revealing another person’s secrets or wrongdoings
1792 • OBSCURE secret, concealed → Sc. obs.
..19C • DATCHIE hidden, secret → Sc.   
………. • HUGGRY-MUGGRY secret, clandestine → Sc.
1804 • POCKET private, secret → obs.
1805 • CONFIDENTIAL enjoying the confidence of another person; entrusted with secrets
1810 • HIDLINGS hidden, secret, underhand, clandestine → Sc. & N. Eng. dial.
1816 • CONFIDANT entrusted with secrets; privy to a secret matter
1824 • SUB ROSA private, secret, confidential
1833 • SNEAKY underhanded or secretive
1835 • HOLE-AND-CORNER secret, private, clandestine
.M19 • UNDER THE BED clandestine, secret, corrupt
………. • UNDER THE TABLE clandestine, secret, corrupt
1850 • DUMMY secretly acting on behalf of someone else
1898 • BLAB-TONGUED talkative; unable to keep a secret → Eng. dial. (Bk.)
..L19 • CLOSE AS AN OYSTER silent, secretive → US sl.
………. • HIDDENMOST most hidden or secret
………. • UNDER ONE’S HAT secret → US sl.
1900 • DUMB AS AN OYSTER silent, secretive → Aust. sl.
1901 • LONG-LUGGED eager to listen to secrets or scandal, given to eavesdropping → Sc.
1909 • SHUT-MOUTHED silent, secretive, reserved → Amer. dial.
1916 • HUSH-HUSH secret → UK military origins
1918 • CLOSE AS AN OYSTER silent, secretive → Aust. sl.
1924 • PINK secret, confidential → military sl., chiefly Navy usage
1928 • UNDER COVER in hiding, secret, clandestine → US criminals’ sl.
1939 • UNDER WRAPS secret → sl.
1944 • HUSH secret
1947 • LEAKY undependable with a secret → Amer. sl. (Bk.)
1948 • CLOSET secret; concealed, not open about something concerning oneself  → US sl.
1950 • CLOSED-DOOR restricted, secret
………. • COPA confidential, secret → sl.
………. • COPACETIC • COPASETIC • KOPASETIC confidential, secret → sl.
………. • COPASETTY confidential, secret → sl.
………. • COPESETTE • KOPASETTE confidential, secret → sl.
………. • COPUS confidential, secret → sl.
1960 • PRIVATED kept private or secret
1976 • QUIET-SIDE secret → US sl.
1990 • DOLO secret → US students’ sl.
1991 • DOWN LOW covert, secret → African-American sl.
1997 • NINJA secretive → US students’ sl.
2000 • BACK ROOM secret, concealed → US sl. (Bk.)

ADVERBS
1000 • DIELICHE secretly → obs.
………. • DIGHENLICHE secretly → obs.
1175 • DERNLY in a secret manner; with secrecy → obs.
1200 • DERNE secretly → obs.
1225 • HIDLINS secretly, stealthily, clandestinely → Sc.
1250 • HIDLINGS in hidden wise, secretly → Sc. & Eng. dial.
………. • PRIVILY secretly, in secret
………. • STILL AND LOUD both in secret and openly; under all circumstances → obs.
1300 • IN HIDEL in concealment, in secret → obs.
1325 • HIDEL-LIKE secretly → obs.
1330 • IN ROUN secretly → obs.
………. • PRIVY privately or secretly; in secret → obs.
1382 • HIDINGLY secretly, privily → obs.
1386 • SECRELY secretly → obs.
1387 • CLOSE secretly, covertly → obs.
1390 • IN SECREE in private, secretly → obs.
1393 • IN PRIVY in secret; in private → obs.
1400 • THEFTUOUSLY by or as by theft; stealthily, secretly → chiefly Sc.
1422 • HIDLINGS in a hidden way, secretly → Sc. & N. Eng. dial.
………. • IN HIDLINGS in secret, secretly → Sc. & N. Eng. dial.
1470 • SECRETEMENT secretly → obs.
1475 • IN SECRETNESS secretly → obs.
1500 • CLOAKEDLY disguisedly, in a secret or underhand way → obs.
1529 • HUGGER-MUGGER secretly, clandestinely
1552 • CLOSELY secretly, covertly, privately → obs.
1559 • DARKLY secretly, in secrecy; without the knowledge of others → obs.
1557 • UNDER THE THUMB • UNDER THUMB secretly, confidentially → obs.
1580 • HIDDENLY in a hidden manner; secretly
1582 • UNDERBOARD in an underhand or secret manner; clandestinely; opposed to above-board
1611 • ABSTRUSELY secretly, in a concealed manner → obs.
1632 • UNDERGROUND in secrecy or concealment; in a hidden or obscure manner
1641 • OCCULTLY in an occult or hidden manner; secretly
1654 • SUB ROSA privately, secretly, in strict confidence
1699 • CLANCULARLY in a clandestine manner; secretly, privately → obs.
1786 • STOWNLINS by stealth; secretly → Sc.
1790 • HUDDLE-MUDDLE secretly → Sc. obs.
1791 • SUBTERRANEOUSLY secretly; covertly; in the dark
1796 • BETWEEN YOU AND ME AND THE POST secretly; in confidence → Amer. dial.
..19C • HUGGRY-MUGGRY secretly → Sc.
1824 • UNDER-THUMB secretly; in an underhand manner → Sc. & Eng. dial.
1841 • SLINKING marked by stealth or secrecy
1859 • SUBTERRANEANLY secretly, clandestinely
1860 • UNDERFOOT quietly, secretly
1866 • SCOUK • SKOOK in a hidden manner, secretly, furtively, with a gloomy, scowling mien → Sc. & Eng. dial.
1867 • ON THE FLY in secret; sneakily → chiefly Sc.
1871 • BETWEEN YOU AND ME AND THE GATE-POST secretly; in confidence → Amer. dial.
1880 • IN CAMERA in private, in secret
1883 • GIVE THE GAME AWAY to reveal some secret or hidden fact, esp. inadvertently
1884 • ON THE Q.T. surreptitiously, on the quiet; secretly → sl.
1888 • BEHIND CLOSED DOORS in private, in secrecy
1893 • ON THE SIDE secretly; often used with reference to extramarital sexual affairs
1898 • BETWIXT YOU AND ME AND THE GATE between ourselves → Eng. dial. (Bk.)
1898 • UNDER BANISTY secretly, surreptitiously → Eng. dial. (Bk.)
..20C • BETWEEN YOU AND ME AND JACK MUM secretly, in confidence → Irish sl.
1904 • SUB ROSA secretly, confidentially → colloq. (Bk.)
1905 • BEHIND HAND in secret, in an underhand way → Sc. (Bk.)
………. • UNBESEEN unobserved, secretly → Eng. dial. (Bk.)
………. • UNDER THE WIND secretly, by underhand means → Eng. dial. (Bk.)
1926 • ON THE STRICT Q.T. secretly, quietly → US sl. (Bk.)
1941 • BETWEEN YOU AND ME AND THE LAMP POST secretly; in confidence → Amer. dial.
1992 • ON THE DOWN-LOW in secret; of a man: secretly engaged in homosexual activity
1995 • ON THE SNEAK TIP in secret → US sl.
1999 • SNIDE secretly; deceitfully → UK sl.
………. • BY THE BACK DOOR secretly or unofficially (Bk.)

NOUNS
1000 • DERN a hidden thing; a secret → obs.
………. • ROUN a secret, a mystery → obs.
………. • THOROUGHFARES the innermost or secret parts of something → obs.
1000 • SUNDER-ROUNDING private or secret conversation or consultation → obs.
1175 • SUNDER-ROUN private or secret conversation or consultation → obs.
1225 • DEEPSHIP a profound secret or mystery → obs.
………. • DERNSHIP secrecy; a secret matter → obs.
………. • DIHELNESS secrecy → obs.
………. • PRIVITY privacy, seclusion; concealment, secrecy, a thing kept hidden or secret → arch.
1250 • DERN secrecy, concealment, privacy → obs.
1300 • TAPINAGE hiding, concealment, secrecy → obs.
1325 • SUNDER-RED private or secret consultation or counsel
1330 • HIDNESS a being hidden, secrecy → obs.
1340 • DERN a secret place; a place of concealment → obs.
………. • SHRIFT revelation of something private or secret → arch.
1375 • COVIN secret contrivance or device; secret intent → obs.
1380 • HIDDENNESS a being hidden; secrecy
1384 • CONVENTICLE a meeting or assembly of a private, secretive, or unlawful nature → obs.
………. • DARKNESS obscurity; mystery, secrecy
1386 • SECRE a private or secret matter → obs.
………. • SECRENESS secretness → obs.
1390 • TAPINAGE hiding, concealment, secrecy → obs.
1400 • DERNHEAD secret matter; a secret → obs.
………. • STILLNESS secrecy → obs.
………. • UNDERCRAFT hidden or secret craft or cunning → obs.
1450 • CLOSET a hidden or secret place; a recess
………. • MEW a secret place; a place of concealment or retirement → obs.
1460 • BLAB babbling; divulging of secrets
1461 • HUDDER-MUDDER concealment, secrecy, privacy → obs.
1475 • HODELNESSE concealment, secrecy → obs.
………. • SECRETNESS secrecy, privacy → obs.
1500 • SCUGGERY concealment, secrecy → N. Eng. dial.
1529 • HUGGER-MUGGER concealment, secrecy
1534 • CONVEYANCE a secret or cunning device, an artifice → obs.
1549 • BACK-SHOP a small private shop behind the main one; a secret place of business
1550 • PRIVITATE a secret matter or business → Sc. obs.
1557 • LONG TONGUE a tendency to speak out of turn or reveal secrets → colloq.
1562 • CLOSENESS secrecy, concealment, reticence → obs.
1570 • AMBAGE a secret, mysterious, or incomprehensible act or practice
………. • COUNTERMINE a secret device or plot designed to frustrate another
1586 • CONEY BURROW a hiding place; a secret place; a retreat → obs.
1592 • COVERTNESS a being covert; secrecy
1597 • HIDLINGS hiding places, secret places;
1601 • ELIMINATION a divulging secrets → obs.
1605 • ARCANUM a hidden thing; a mystery, a profound secret → plural form = ‘arcana’
1610 • DIVULGATION the divulging of something secret or private
1611 • RECESS a secret or private place
1624 • PRIVACY the keeping of a secret; reticence → obs.
1625 • PRIVACIES private or personal matters; secrets
1635 • CABAL a secret → obs.
1641 • BACKSTAIRS a secret disingenuous method of approach
1645 • CRYPTOLOGY secret communication; coded or enigmatic language or writing
1646 • RECESS a hidden part, a secret → obs.
1649 • UNDERDEALING underhand or secret action → obs.
1651 • SUPPRESSION a keeping something secret; refusal to reveal or disclose
1654 • HUGGER-MUG concealment, secrecy → obs.
1656 • OCCULT something hidden or secret → obs.
1660 • COMPLOTMENT secret design, plan → obs.
1663 • CRYPTIC something enigmatic or hidden; a secret, a mystery
1682 • CLANDESTINITY secrecy, privacy
1687 • CLOSETING discussion in private or in secret
1699 • IVY-BUSH a place of concealment or retirement; a secret place, a hiding place
1778 • SNUGNESS secrecy, reticence → obs.
..19C • CUDDLE-MUDDLE a secret conversation, often, with evil intent → Sc.
1814 • UNDERWORK underhand or secret work
1817 • CONCILIABULE a small private or secret assembly
1823 • HIDLINGS secret or clandestine operations
1825 • BABBLEMENT indiscreet or inappropriate disclosure of information or a secret → obs.
1839 • APOCRYPHA hidden things; secrets
………. • CAMARILLA a body of secret intriguers
1840 • MILK IN THE COCONUT the secret; the heart of the matter
1841 • MASONRY secret signs and passwords → obs.
1842 • DUMMYISM a secretly acting on behalf of someone else
1857 • SECRET DE POLICHINELLE a supposed secret which is generally known; an open secret
1862 • CUGGER-MUGGER a confabulation, a secret conversation; a whispering, a gossiping in a low voice → Ireland
1863 • LOOSE LIPS indicates a tendency to reveal secrets or to speak indiscreetly
1870 • HIDDEN HAND a secret or occult influence, esp. of a malignant character
1873 • HOLE-AND-CORNERISM a system of secret procedure
1878 • A HEN ON an urgent, important, or secret plan or project in the making → Amer. dial.
1881 • DEAL an underhand or secret transaction; a trade of questionable legality; a mutually beneficial commercial or political arrangement → US sl.
1887 • COLLOGUE a private talk; a secret plan or scheme
1898 • CAB a small number of persons secretly united in the performance of some undertaking → Eng. dial. (Bk.)
..L19 • MASONICS secrets → UK society sl.
1905 • TICHEL any article kept secretly → Sc. (Bk.)
1910 • INÉDIT something secret or unrevealed
1928 • BLOW secret information or warning → sl.
1929 • HUDDLE a secret conference → colloq.
1942 • BUG UNDER THE CHIP a secret → Amer. sl. (Bk.)
………. • DEAD QUIET absolute secrecy → Amer. sl. (Bk.)
………. • HUSH-HUSH • HUSH-HUSH STUFF a secret → Amer. sl. (Bk.)
………. • MUM a secret → Amer. sl. (Bk.)
………. • NO-CAN-TELL a secret → Amer. sl. (Bk.)
………. • THIN SECRET a secret easily seen through → Amer. sl. (Bk.)
1945 • BIGOT highly secret information; a code word → World War II Amer. sl.
1948 • COVEN a group or association, esp. one viewed as secretive, exclusive or sinister → depreciative usage
1949 • A HEN ON THE NEST an urgent, important, or secret plan or project in the making → Amer. dial.
1963 • TREFF a secret meeting, esp. for the transfer of goods or information → espionage sl., orig. US
1985 • IRISH WHISPER a saying something aloud when whispering would have been more appropriate, as a secret → Amer. dial.
1989 • SNEAK GO any secretive action → Aust. sl.
2006 • DIRT gossip; scandal; incriminating secrets → US sl. (Bk.)

NOUNS, PERSON
1225 • CACKLE one who chats or gossips; a telltale, tattler, or blabber; one who divulges a secret → sl.
1374 • BLAB an open-mouthed person; one who has not sufficient control over his tongue; a revealer of secrets or of what ought to be kept private; a babbler, a tattler, a telltale
1375 • BLABBERER one who reveals secrets; a telltale, a tattler
1386 • LAB • LABBE a blab; a telltale; a great talker; a chatterbox; a gossip; one who cannot keep a secret → obs. exc. Eng. dial.
1400 • CACKLER one who chats or gossips; a talkative person; a telltale, tattler, or blabber; one who divulges a secret → sl.
………. • TITTLER a person who spreads rumours quietly and secretly; a telltale → colloq.
1440 • BEWRAYER he who bewrays or reveals; a person who discovers a thing which should be concealed; a divulger of secrets; a  betrayer
1547 • WHISPERER a person who communicates something secretly or quietly; a secret slanderer or talebearer
1555 • BABBLER one who tells too freely what he knows; a prating gossip; a teller of secrets; a blabber; a talebearer
1557 • BLABBER one who blabs; one who reveals secrets; a telltale
1562 • LONG TONGUE a person who tends to speak out of turn or reveal secrets → colloq.
1576 • COUNSEL-KEEPER a person who is trusted to keep secrets by another; a confidant → arch.
1601 • MOLE a person who works in darkness or in secrecy
1607 • SYMMIST • SYMMYST an associate in a ‘mystery’, i.e. a secret belief or practice → obs.
1616 • SIEVE a person who cannot keep a secret
1645 • CONFIDENT a person entrusted with secrets or private matters
1744 • SILENTIARY someone sworn to keep state secrets
1746 • LAB-O’-THE-TONGUE a chatterbox, tattler; one who cannot keep a secret → Eng. dial.
1808 • TALE-PAT a telltale, a talebearer, one who divulges secrets → Sc.
………. • TALE-PYET a telltale, a talebearer, one who divulges secrets; an informer, a tattler → Sc. & Eng. dial.
1822 • GAB one who talks excessively; a loquacious speaker; a chatterbox; a tattler; one who cannot keep a secret → Sc.
1840 • DUMMY a person who secretly acts on behalf of someone else
1847 • LONG-TONGUE a chatterbox, talebearer, telltale, gossip, blabber, a divulger of secrets; an unusually talkative woman; a scold
1862 • HUGGER-MUGGER a person who keeps things hidden or in secret; a hoarder or miser
1871 • FOX IN THE HENHOUSE a person who is secretly acting against the interests of the community or organization to which he belongs
1886 • BLOB-TONGUE one who blurts out a secret; a telltale; a blab; a gossip → Eng. dial.
1889 • TATTLE-TALE one who discloses confidences or secrets; one who informs on or betrays others; a telltale; a talebearer; a whistle-blower → colloq, orig. US
1891 • SHUT-MOUTH a person who says little; a silent, secretive or reserved person → Amer. dial.
1905 • OPEN-GOB a talkative person; one who reveals secrets → Eng. dial. (Bk.)
1913 • MYSTERY WOMAN a secretive or enigmatic woman; a woman about whom little is known
1916 • BLABBERMOUTH one who reveals secrets, a telltale, a gossip, an indiscreet talker → sl., orig. US
1917 • DARK HORSE a person who keeps things about themselves secret → Aust. sl.
1922 • MYSTERY MAN a man about whom little or nothing is known; a secretive man
1949 • BLOBBER-MOUTH a talkative person; one who will not keeps secrets → Amer. dial.
.M20 • CLOSET CASE anyone who does anything in secret → US colloq.
1969 • LEAKER a person who discloses secret information or allows it to be disclosed
1970 • MOUTHAR a chatterbox; a gossip; one who cannot be trusted to keep secrets → W. Indies
1974 • MIGHTY MOUTH someone who talks too much and spreads gossip or reveals secrets → sl.
1975 • BASKET a person who can’t keep a secret → Amer. dial.
1977 • BLABBERGUTS one who talks too much or betrays secrets; a gossip; a telltale → US sl.
1988 • MOUTH a person who is a gossip; one who is known to divulge confidences or secrets → Aust. sl. (Bk.)
1990 • MOUTHY GUY one who cannot keep a secret
2006 • BIG MOUTH a person who tells secrets; someone who talks too much or too loudly → US sl. (Bk.)

PHRASES
1384 • IN PRIVY OR APERT secretly or openly; in private or in public→ obs.
1586 • NOT TO TELL ONE’S SHIRT to keep a matter strictly secret, not tell a soul → obs.
1600 • IN PRIVY OR PLAIN secretly or openly; in private or in public→ obs.
1704 • MUM’S THE WORD used as injunction not to reveal a secret → sl.
1830 • BETWEEN YOU AND ME AND THE BED-POST in all confidence or secrecy
1832 • SECRET AS THE GRAVE kept as a close secret
1939 • UNDER WRAPS kept in secret → UK sl.
2000 • QUIET IS KEPT used to request secrecy after making a revelation → African-American sl.

VERBS
..893 • DERN to hide, to conceal, to keep secret → obs.
1000 • HEEL to hide or conceal something; to keep something secret; also, to keep a secret, to keep silence
………. • WRY to keep secret or unrevealed; to conceal or hide a matter → obs.
1300 • BEWRAY to expose a person by divulging his or her secrets → obs.
………. • DILL to conceal, to hide, to keep secret → obs.
1375 • LURK to move about in a secret and furtive manner
1377 • LAB to blab, to let out secrets → obs. exc. Eng. dial.
1386 • BEWRAY to divulge or revel secrets prejudicially → arch.
1393 • KEEP COUNSEL to maintain confidentiality or secrecy; to keep a secret
1400 • KEEP A MATTER IN COUNSEL to keep a matter confidential or secret → obs.
………. • TITTLE to spread gossip quietly or secretly → colloq.
………. • UNCLOSE to disclose something secret or hidden → chiefly literary usage
1402 • SHROUD to conceal in a secret place, or in a secret manner → obs.
1425 • PURSE to keep secret; to keep back, to contain, to confine → obs.
1484 • CELE to hide, to conceal, to keep secret → obs.
1532 • KEEP DARK to keep secret, to keep something concealed → colloq.
1535 • BABBLE to reveal a secret by speaking indiscreetly
1541 • SUBORN to obtain something in a secret or underhand manner
1556 • TELL TALES OUT OF SCHOOL to repeat private or secret manners
………. • TITTLE-TATTLE to reveal others’ secrets
1575 • BLOW to speak revealingly; to give away secret information
1570 • WHIST to be silent about; to keep secret → obs.
1579 • PLAY AT HANDY-DANDY • PLAY HANDY-DANDY to act secretively or frivolously
1597 • HEAR A BIRD SING to receive private or secret information
1600 • HUGGER to conceal, to keep secret → Eng. dial.
1605 • DISCABINET to reveal or disclose something secret or hidden
1607 • EVISCERATE to bring out the inmost secrets of → obs.
………. • WORM to pry into the secrets of a person; to play the spy upon → obs.
1608 • BE OF A PERSON’S BOSOM to be entrusted with his or her secrets → obs.
………. • ELIMINATE to divulge something meant to be kept secret → obs.
1616 • BLAB to reveal or betray secrets
1649 • CLOSET to conspire or scheme in secret to do something → obs.
1659 • UNBOSOM to disclose or reveal one’s secrets, thoughts, etc.
1672 • TRINKLE to treat secretly or in an underhand way; to intrigue with → obs.
1678 • KEEP UP to keep secret or undivulged → obs.
………. • VENT to disclose, to divulge, or let out a secret, etc. → obs.
1680 • BLUTTER to give hasty utterance to; to blurt out; to talk foolishly; to tell what ought to be kept secret → obs. exc. Sc.
1695 • UNDERWORK to work secretly; to take clandestine measures → obs.
1698 • CACKLE to talk idly, esp. in the sense of telling secrets → criminals’ sl.
1703 • LANE to conceal, to keep secret, to connive at → Sc. & Eng. dial. obs.
1716 • WORM OUT to extract a secret or information by insidious questioning
1750 • LET THE CAT OUT OF THE BAG to disclose a secret or a trick
1768 • HEAL to hide, to conceal; to keep secret → Sc. & Eng. dial.
..19C • COLLIFOBBLE to talk secretly together → Eng. dial.
………. • UNDERFIND to discover something secret; to find out → Eng. dial.
1803 • HUGGER-MUGGER to keep secret or concealed
1804 • LET THE CAT OUT OF THE WALLET to give away a secret or tell a piece of news too soon; to let the cat out of the bag → Amer. dial.
1812 • BLOW THE GAFF to let out a secret; to reveal a plot; to give convicting evidence → sl.
1827 • HEAL ON A PERSON to keep anyone’s secrets, not to betray or reveal them → Sc.
1845 • SCOUK • SKOOK to skulk; to scowl; to look angry, sulky, or furtive; to go about in a secret, guilty manner → Sc.
.M19 • SPLIT to disclose, to reveal secrets → sl.
1866 • CUDDLE-MUDDLE to speak in a secret, muttering voice → Sc. (Bk.)
1879 • GIVE THE SHOW AWAY to reveal some secret or hidden fact, esp. inadvertently
1881 • WARD to carefully keep a secret
1883 • GIVE THE GAME AWAY to reveal some secret or hidden fact, esp. inadvertently
1891 • BLASH to make public, to reveal secrets → Eng. dial.
1897 • CLAP THE THUMB ON to keep secret, to conceal; to remain silent → Sc. 
………. • GUMSHOE to behave or move in a secret or surreptitious way; to sneak about → colloq., orig. US
1898 • BLARE to let out secrets, to blab → Eng. dial. (Bk.)
………. • BLART to let out a secret; to spread abroad news or scandal → Eng. dial. (Bk.)
………. • BLOACH to divulge secrets; to blab → Eng. dial. (Bk.)
..20C • CRACK HARDY to keep a secret → Aust. sl.
………. • LET SOMEONE IN ON to impart otherwise secret or privileged information → sl.
1903 • CHEEP to tell or reveal; to betray a secret; to mention, to hint at → Amer. dial.
1905 • PUT ONE’S THUMB ON IT to keep secret, to conceal; to remain silent → Sc. 
………. • QUATCH to betray; to tell a secret → Eng. dial. (Bk.)
………. • RAP OFF to speak inconsiderately; to let out secrets → Eng. dial. (Bk.)
………. • YED to work secretly; to conquer by stratagem → Eng. dial. (Bk.)
1908 • PASS to pass on gossip, to tell tales, to betray confidences → Sc. 
1909 • BLATE OUT to blurt out, esp. a secret → Amer. dial.
………. • PUT A BUG IN ONE’S EAR to tell one a secret or put one on to a secret; to give somebody a hint for his own good → Amer. dial.
………. • TIP THE OFFICE to betray a secret → sl.
1910 • BLOW OFF ONE’S MOUTH to talk too much; to reveal a secret → US sl., arch. 
………. • BLOW OFF ONE’S TRAP to talk too much; to reveal a secret → US sl., arch. 
………. • BLOW OFF ONE’S YAP to talk too much; to reveal a secret → US sl., arch. 
1913 • CLATFART to reveal a secret by speaking indiscreetly → Eng. dial.
1916 • HAVE A HEN ON to have an urgent, important, or secret plan or project in the making → Amer. dial.
1919 • SPILL THE BEANS to reveal a secret → sl., orig. US
1927 • KEEP ONE’S GUTS to keep a secret, to be discreet → Amer. dial.
1929 • GO INTO A HUDDLE to hold a secret conference → colloq.
1940 • KNOW WHERE THE BODIES ARE BURIED to have personal knowledge of the secrets or confidential affairs of an organization or person → orig. US
1949 • HAVE A HEN ON THE NEST to have an urgent, important, or secret plan or project in the making → Amer. dial.
1960 • LABA-LABA • LABBA-LABBA to chatter, to gossip; to betray secrets → W. Indies
………. • SCREAM ON ONE to give away a secret or to betray the confidence of someone; to tell; to inform; to attack → African-American sl.
1965 • DROP A BUG IN ONE’S EAR to tell one a secret or put one on to a secret; to give somebody a hint for his own good → Amer. dial.
………. • HAVE SOMETHING UNDER ONE’S COAT to be keeping something secret; to have something up one’s sleeve → Amer. dial.
1967 • EAT COOTER LIVER to tell a secret → Amer. dial.
………. • LET THE CAT OUT OF THE SACK to disclose a secret → Amer. dial.
1969 • QUIDDLE to give away a secret or tell a piece of news too soon → Amer. dial.
1970 • FERSCHNAPP ONESELF to let the cat out of the bag, to reveal a secret → Amer. dial.
………. • KEEP A STIFF LIP to keep quiet, to maintain a secret → African-American sl.
………. • PUT ONE’S BUSINESS IN THE STREET to tell one’s secrets → US students’ sl. (Bk.)
1975 • BLAB OFF  to reveal a secret; to say what  is better left unsaid → US sl. (Bk.)
2006 • BIG-MOUTH to spread secrets around → US sl. (Bk.)
………. • BLABBERMOUTH to tell secrets in public → US sl. (Bk.)
………. • PUT SOMEONE ON FRONT STREET to expose someone’s secrets in public → African-American sl.