unctuous
1. [ adjective ] unpleasantly and excessively suave or ingratiating in manner or speech
Synonyms: oily fulsome oleaginous smarmy buttery
Examples:

"buttery praise" "gave him a fulsome introduction" "an oily sycophantic press agent" "oleaginous hypocrisy" "smarmy self-importance" "the unctuous Uriah Heep"

Related terms: insincere
Similar spelling:   unctuously
  unstudious
  unction
  unstrung