/ Dictionary / Index U unstopper: Meaning and Definition of Find definitions for: un•stop•per Pronunciation: (un-stop'ur), [key] — v.t. to unstop. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. unstoppable unstoried Related Content Daily Word Quiz: fabricate Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language