a suffix of nouns of quality, state, office, etc., many of which accompany adjectives in -acious or nouns or adjectives in -ate: fallacy; papacy; legacy; delicacy; piracy.
Origin of -acy
< Latin-ācia,-ātia (spelling interchangeably in Medieval Latin, reflecting the Rom merger of the forms); these are in turn complexes of -āc- and -āt--ate1 + -ia-y3. Cf. -cracy
