the idea that you can ask somebody to pay for you (for something like food or a drink) and tell them that you will pay them back, though you have no intention to pay them back at all
Pay back theory in action:
Mike: "Hey Jason, I don't have any money on me, so could you pay for me when we eat today? I'll pay you back... "
Pay-back-ism is a term used by thugs/187 empire meaning the opposite of revenge-ism more of just compensation and maybe a little more then just payback more like a reckoning- ism :go to definition in Urban