/ Dictionary / Index D dud: Meaning and Definition of Find definitions for: dud Pronunciation: (dud), [key] — n. a device, person, or enterprise that proves to be a failure. a shell or missile that fails to explode after being fired. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: dud (Thesaurus) ductwork duddy Related Content Daily Word Quiz: candid Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language