unctuousexcessively or ingratiatingly flattering; oily and sycophanticThe salesman's unctuous manner made potential buyers suspicious rather than reassured.NoteThe salesman's unctuous manner made potential buyers suspicious rather than reassured.Elon.io is an online learning platformWe have an entire course teaching GRE Verbal — Essential Vocabulary grammar and vocabulary.Start learning GRE Verbal — Essential Vocabulary now