WordNet sense 1 (unpleasantly and excessively suave or ingratiating in manner or speech):

buttery, fulsome, oleaginous, smarmy, soapy, unctuous

WordNet sense 2 (lacking sincerity):

insincere

WordNet sense 3 (having a coating; covered with an outer layer or film; often used in combination):

coated

WordNet sense 4 (containing an unusual amount of grease or oil):

greasy, sebaceous

WordNet sense 5 (containing or composed of fat):

fatty

WordNet sense 6 (soiled or likely to soil with dirt or grime):

dirty, unclean, soiled