A "Promise" is an insult or a nickname for someone or
something who has done something wrong / is the worst, an insult for
everything. Not too rude, not too kind.
You can use the
word "Promise" for anything, anyone, no matter what they have done, it is the best insult.
Dave: Hey man, did you like that twilight movie
Greg: Fuck you, Promise.
Dave: Sorry for stealing your
girlfriend.
Greg: Fucking Promise.
Dave: Hey man, you no that
Jim kid?
Greg: Yeah bro, he's a fucking promise hey.