Someone who chooses to be difficult in normal situations. Anyone who doesn't want to do something that you want to do and makes a situation annoying. Any annoying person. Anyone who pisses you off periodically for a long period of time.
Rob: Lets go down to the caf for some food.
Daria: No, I just ate and I don't feel like it.
Rob: Stop being such a fuckin' punany biatch.
Rpb: Sara, find me some calomine lotion for my poison ivy.
Sara: Ive been looking! I can't find it!
Rob: Wow you are such a fuckin' punany biatch.