/ Dictionary / Index M mess-up: Meaning and Definition of Find definitions for: mess-up Pronunciation: (mes'up"), [key] — n. a blunder; state of confusion; mix-up. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: mess-up (Thesaurus) messuage messy Related Content Daily Word Quiz: vertigo Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language