Unctuous
/ˈʌnktʃuəs/
adjective
(of a liquid or substance) Oily or greasy.
(of a wine, coffee, sauce, gravy etc.) Rich, lush, intense, with layers of concentrated, soft, velvety flavor.
(by extension, of a person) Profusely polite, especially unpleasantly so and insincerely earnest.
Synonyms: oleaginous, saponaceous, slimy, savorous, creepy, effusive, groveling, oleaginous