oleaginous

Ragoravich is predictably oleaginous, a man with a file cabinet full of hidden agendas, but he is charmingly persuasive, and the money has already been wired into Maggie’s account.

Already masterwork in balancing gentility with explosive rage, the actor blends the spark of a political mover with the oleaginous menace of a mob boss.

But the most villainous entity they encounter is a duplicitous schemer played with oleaginous insincerity by Hugh Grant.

It's easy for this approach to look rather oleaginous.

Last night he suggested in his usual oleaginous way that mean people on Twitter are worse than a dictator who poisons and imprisons his political adversaries.