/ Dictionary / Index O opponency: Meaning and Definition of Find definitions for: op•po•nen•cy Pronunciation: (u-pō'nun-sē), [key] — n. an act or instance of opposing. the state of being an opponent. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. oppilate opponent Related Content Daily Word Quiz: spectral Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language