/ Dictionary / Index R retroaction: Meaning and Definition of Find definitions for: ret•ro•ac•tion Pronunciation: (re"trō-ak'shun), [key] — n. action that is opposed or contrary to the preceding action. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. retroact retroactive Related Content Daily Word Quiz: censure Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language