/ Dictionary / Index O overactive: Meaning and Definition of Find definitions for: o•ver•ac•tive Pronunciation: (ō"vur-ak'tiv), [key] — adj. exceptionally or excessively active; too active. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: overactive (Thesaurus) overact overage Related Content Daily Word Quiz: fabricate Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language