/ Dictionary / Index U unsuccessful: Meaning and Definition of Find definitions for: un•suc•cess•ful Pronunciation: (un"suk-ses'ful), [key] — adj. not achieving or not attended with success: an unsuccessful person; an unsuccessful venture. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: unsuccessful (Thesaurus) unsuccess unsuitable 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