v.1. Sports To play a game that breaks a tie in ranking: The top two teams play off tonight to determine the champion.
2. To perform an action in response to some other action, exploiting it advantageously: A good tennis player plays off every move the opponent makes. We make a good team, since we play off each other perfectly.
3. play off against To set something in opposition to, or working in a different direction than, something else in order to gain an advantage: The queen played the nobles off against each other, telling each of them that the others were plotting against him.