/ Dictionary / Index M mendacious: Meaning and Definition of Find definitions for: men•da•cious Pronunciation: (men-dā'shus), [key] — adj. telling lies, esp. habitually; dishonest; lying; untruthful: a mendacious person. false or untrue: a mendacious report. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: mendacious (Thesaurus) mend mendacity Related Content Daily Word Quiz: philtrum Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language