Noun: Refers to an acquaintance, FaceBook friend, classmate, work associate, indirect friend, (e.g. a good friend's friend), or any individual not quite within the realm of closeness required to be deemed a "real" friend.
Coined from the "sup dude" slurred toward supdudes when passing by since there is simply no other interaction or common experience worth sharing.
*Supdude is a completely subjective term such as "friend" or "brother." A supdude to one could be a friend to another.
"How was the party?
"It sucked it was just me and a bunch of supdudes."
When you and someone else are in an argument, and the other person says they are better than you (scored more goals in a game, got a better grade, etc.) and you tell them you got the better grade or what not, adding on the end, "sup dude?" in a nonchalant manner, just to rub it in.
Jake- "Hey man, how'd you do on the test last week?"
Mike- "I got a 95, how'd you do?"
Jake- "I got a 98, sup dude?"