/ Dictionary / Index H hyperactivity: Meaning and Definition of Find definitions for: hy•per•ac•tiv•i•ty Pronunciation: (hī"pur-ak-tiv'i-tē), [key] — n. the condition of being hyperactive. hyperkinesia. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: hyperactivity (Thesaurus) hyperactive hyperadenosis Related Content Daily Word Quiz: abscond Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language