/ Dictionary / Index M muckworm: Meaning and Definition of Find definitions for: muck•worm Pronunciation: (muk'wûrm"), [key] — n. (not in technical use) the larva of any of several insects, as the dung beetle, which lives in or beneath manure. a miser. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. muck-up mucky Related Content Daily Word Quiz: entomology Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language