These adjectives mean lacking honesty or truthfulness. Dishonest is the least specific: a dishonest business executive. Lying conveys a blunt accusation of untruth: a lying witness giving inconsistent testimony. Untruthful is a softer term and suggests lack of veracity and divergence from fact: made an untruthful statement. Deceitful implies misleading by falsehood or by concealment of the truth: deceitful advertising.Mendacious is more formal than lying, and suggests a chronic inclination toward untruth: a mendacious and troublesome employee.