One who balls like a pro. If someone is baller at absolutely anything, he/she has the right to call themselves a pro baller. A pro baller tends to be "the shit".
Jon: "Nirman makes everything hilarious!"
Frank: "Yeah, and he a beast on the court."
Jon: "What a pro baller."
One who acts like he is superior or better at something than someone else at a certain activity but is really awful at it and no one wants to tell him how pathetic he is.
Guy 1: Dude i put up like 2 points last night!
Guy 2: What a baller!!!!!
Guy 3: Yeah looks like we got ourselves a pro baller over here