What is Pay off ?
Pay off is (verb) 1. to finish paying money which is owed He’s aiming to pay off his mortgage in ten years. She said she couldn’t pay off the loan. 2. to pay all the money owed to someone and end his or her employment When the company was taken over the factory was closed and all the workers were paid off. 3. to be successful Their more cautious approach eventually paid off. All that hard work paid off when she came top of her class.
source: Easier English, Student Dictionary Upper Intermediate Level