SUP means What’s Up?
SUP is an abbreviation of What’s Up. In the internet world or even in reality, SUP has replaced words like hello or hi. It sometimes means, whats’s new?. Whenever you meet someone, you can ask him/her, SUP?
Sample Usage in Conversation
Ned: SUP?
Joffrey: Nothing.
Joffrey: SUP with you?
Ned: Nothing