\men-'da-shes\ adj.: given to or characterized by deception or falsehood or divergence from absolute truth
Liza wasn't about to fall for the unrealistic claims being touted by the mendacious car salesman.
Did You Know?
"Mendacious" and "lying" have very similar meanings, but the two are not interchangeable. "Mendacious" is more formal and literary, suggesting a deception harmless enough to be considered bland. "Lying" is more blunt, accusatory, and often confrontational. You might yell, "You lying rat!" in an argument, but you would likely stick to the more diplomatic "Aren't you being somewhat mendacious?" in a business meeting. "Mendacious can also imply habitual untruthfulness, whereas "lying" is more likely to be used to identify specific instances of dishonesty.