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.

Briefly, "the realization that each random passerby is living a life as vivid and complex as your own." Originally from the Dictionary of Obscure Sorrows, which has a lot more beautiful neologism definitions like this you might enjoy.

A person who is in love with himself/herself and his/hers oppinions and displays this by showing subtle contempt of people of a different opinion, class or personality. He/she also belittles other people and his/her relations to them aren't even skin deep, but merely superficial consisting mostly of remarks and comments the smarmy person thinks are cute, but which makes ordinary people sick. The smugness of a smarmy person is almost as big as his/her ego (which is enormous). A smarmy person usually doesn't have a real reason for his/her behavior, but it makes him/her feel important.

A certain attitude often accompanied by a squinty look and a superior smile that makes you instantly hate a person. Similar to snobby.

behavior not unlike Eddie Haskell (in Leave It To Beaver) or Tristan Farnon (in All Creatures Great and Small)

being a slimy, two-faced, back-stabbing, ego-centric arse

A sleazy, insincere demeanor, possessed by one who puts on a fake smile and has ill intent. One who is not what they appear to be. A sales person who uses phrases like "pull the trigger"

sleezy, self-centered and insincere. one whom has his own agenda which conflicts with the interests of others. very fake and/or two-faced.