Nouns Ending in -Ancy &- Ency

Origins & Usage Notes •

• Both suffixes are often used to form nouns and they behave very much like –ance and –ence, but –ancy usually denotes quality, state, or condition (as opposed to the sense of action or progress often expressed by –ance).
• Nouns made from verbs ending in –ate may have the spelling –ancy, e.g. hesitancy (from hesitate), vacancy (from vacate).
• Modern usage tends to confine –nce to action, and to express quality or state by –ncy, e.g. compliance, pliancy; annoyance, buoyancy.
• Nouns with a soft c or g before the ending are often spelled –ency, e.g. emergency (from emergent), complacency (from complacent).
• When the same word exists in both the –ence and the –ency forms, –ence tends to be restricted to action or process in order to connect its meaning rather with that of the verb (where the sense of the verbal etymon permits) than with that of the adjective. –Ency, in contrast, tends to express quality. Compare: coherence and coherency; persistence and persistency.
• In cases where both forms –ence and –ency of a word have equally the sense of quality or condition:
  • most of the time, either of the forms has become obsolete or archaic;
  • where they are both in current use, –ency usually has a more distinct reference to the sense of the related adjective or noun in –ent, considered as the predicate of the subject, e.g. ‘sentience is an attribute of animals’ but ‘some maintain the sentiency of plants’.