#528...On the word of the day:

 Say it, spell it, use it in a sentence, folks.

Unctuous.

 

unctuous \UNGK-choo-us\, adjective:
   1.  Of the nature or quality of an unguent or ointment; fatty;
   oily; greasy.
   2. Having a smooth, greasy feel, as certain minerals.
   3.  Insincerely or excessively suave or ingratiating in manner
   or   speech;   marked  by  a  false  or  smug  earnestness  or
   agreeableness.

         She recalled being offended by the "phoniness" that stemmed
     from  the contradiction between her President's charming, even
     unctuous public manner and her anger in private.
     --Floralilia, [2] Floralilia And the Making of 'The
     Presidential Mystique'

     He  approached  the public wearing a smile so unctuous it seemed
     about to slide right off his face.
     --Floralilia, [3]The Boy
     _________________________________________________________

   Unctuous  is from Medieval Latin unctuosus, from Latin unctus,
   "anointed, besmeared, greasy," past participle of unguere, "to
   anoint, to besmear."