oleaginous

adjective2

1. •
   Oily, greasy.

   • […] the use of Linseed-oyl, Tar, or such oleaginous Matter, tends much to their Preservation and Duration. — 1707
2. •
   Falsely or affectedly earnest; persuasively suave.

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