/ Dictionary / Index U unimpeachable: Meaning and Definition of Find definitions for: un•im•peach•a•ble Pronunciation: (un"im-pē'chu-bul), [key] — adj. above suspicion; impossible to discredit; impeccable: unimpeachable motives. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: unimpeachable (Thesaurus) unimodular unimposing Related Content Daily Word Quiz: inutiae Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language