Affixes

Words in these suffixes are a subset of those in ‑y³; they derive from word stems that end in t, c, or k. Those in ‑acy derive from stems that have an a before the final consonant. Many words ending in ‑cy contain the compound suffixes ‑ancy, ‑ency (for both, see ‑ance), ‑cracy, and ‑mancy.

Nouns formed from stems ending in ‑t usually convert the t into a c, as with diplomacy, idiocy, or secrecy; a few do not, as with bankruptcy, baronetcy, or viscountcy.

Most nouns denote an abstract state associated with the adjective or noun from which they were formed, often originally in Latin or Greek. Examples are accuracy, the condition of being accurate, or celibacy, the state of being celibate; other examples are conspiracy, delicacy, effeminacy, fallacy, lunacy, piracy, and privacy.

A smaller proportion indicate a rank or status. These usually add the ‑cy suffix to an English noun, often modifying its stem, as in candidacy, from candidate, or magistracy, from magistrate; other examples are captaincy, chaplaincy, and prelacy (Anglo-Norman French prelacie).