FAITHLESS, FAITHLESSNESS
ADJECTIVES
► FEDIFRAGOUS breaking a pledge or agreement, faithless, perfidious → 1600 obs.
► INFIDOUS faithless, unfaithful; not to be trusted → 1656 obs.
► PERFIDIOUS guilty of breaking faith or violating confidence; deliberately faithless; treacherous; deceitful and untrustworthy → 1538
NOUNS
► FALSEHOOD as an attribute of persons: falseness, deceitfulness, mendacity, faithlessness → 1297 obs.
► PUNIC FAITH treachery, faithlessness; bad faith → 1590
NOUNS – PERSON
► HALF-MARROW a faithless spouse → 19C sl.
Lexicophilia 