/ Dictionary / Index K know-it-all: Meaning and Definition of Find definitions for: know-it-all Pronunciation: (nō'it ôl"), [key] — n. a person who acts as though he or she knows everything and who dismisses the opinions, comments, or suggestions of others. —adj. of or characteristic of a know-it-all. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: know-it-all (Thesaurus) knowing knowledge Related Content Daily Word Quiz: braggart Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language