/ Dictionary / Index U undeceive: Meaning and Definition of Find definitions for: un•de•ceive Pronunciation: (un"di-sēv'), [key] — -ceived, -ceiv•ing. to free from deception, fallacy, or mistake. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: undeceive (Thesaurus) undecagon undecided Related Content Daily Word Quiz: procrastinate Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language