From The Concise Oxford Dictionary, 1966 Edition:
smarmy, adj. Unctuously ingratiating, fulsome. [from smarm, variation of dialect smalm, to smooth down (as with grease)]
For when "smug" just won't cut it, and you need a really descriptive word for someone just dripping with a tangible, sickeningly oily overinflated sense of self-worth who is hoping for the adulation of the masses, break out "smarm," and variations thereof. Mostly used on chiselled hero-types, like John Sheirdan from Babylon 5 or Shatner, lotharios and erstwhile authority figures.
See also: Smug Mode