oleaginous

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.

Naturally, the oleaginous Senator from Texas, Ted Cruz, got in on the act:

By late Thursday even the oleaginous Ted Cruz was backtracking as fast as he could while Hawley whined on Twitter about his book on Big Tech being canceled due to his actions.