Forwardly and unknowingly exuding lightly overbearing and somewhat slimy behavior. One who would stab you in the back if he or she could get away with it. One who would sell their own mother's soul for benefit and/or attention. A subtle scumbag, sleezball, wretch, or creepshow.
If that smarmy guy comes by my desk again today, I hope I am away at a meeting.