oleaginous

Oily, greasy.

[…] the use of Linseed-oyl, Tar, or such oleaginous Matter, tends much to their Preservation and Duration.

Looking back, it seemed to me that a slight oleaginous mist was still hovering round the chair.

Falsely or affectedly earnest; persuasively suave.

The oleaginous salesman convinced me to buy a more expensive car.

Cruz was obviously analogizing Bernie Sanders to the Bolsheviks and Hillary Clinton to the Mensheviks. The oleaginous Texan is an erudite slyboots, but his history is off-kilter.