/ Dictionary / Index D dumbo: Meaning and Definition of Find definitions for: dum•bo Pronunciation: (dum'bō), [key] — n., pl. adj. -bos, —n. a stupid person: a class full of dumbos. —adj. stupid or foolish: What a dumbo idea! Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. dumbhead dumb sheave Related Content Daily Word Quiz: impetuous Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language