INDISPENSABILITY, INDISPENSABLE
ADJECTIVES
► RIGHT-HAND of a person: of great importance or value to another; serving as an indispensable helper or assistant to another → c1225
► SINE QUA NON indispensable, absolutely necessary or essential → 1615
► SINE-QUA-NONICAL indispensable → 1816
NOUNS
► NECESSARINESS the fact of being necessary; indispensability, necessity → 1551
► SINE QUA NON something indispensable → 1602
► SINE-QUA-NONNINESS indispensability → 1834
NOUNS – PERSON
► RIGHT-HAND a person who is particularly useful or important to another, or upon whom one relies; a chief assistant, an indispensable helper → 1538
► SINE QUA NON somebody or something indispensable → 1602
Lexicophilia 