/ Dictionary / Index A antivitamin: Meaning and Definition of Find definitions for: an•ti•vi•ta•min Pronunciation: (an"tē-vī'tu-min, an"tī- or, Brit., -vit'u-min), [key] — n. Biochem. any substance that interferes with the action of a vitamin. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. antivenin antivivisectionist Related Content Daily Word Quiz: paradox Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language