/ Dictionary / Index M mordacious: Meaning and Definition of Find definitions for: mor•da•cious Pronunciation: (môr-dā'shus), [key] — adj. biting or given to biting. sharp or caustic in style, tone, etc. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: mordacious (Thesaurus) morceau* mordancy Related Content Daily Word Quiz: panacea Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language