Other forms: requitals
When you pay someone back or return their favor, that's requital. Your friend might insist that no requital is necessary for the cookies she gives you, but you may want to bake cupcakes for her tomorrow anyway.
Use requital for the sincere return of a favor, like going to your brother's band concert after he's dutifully attended your poetry reading. You can also use it for retribution for a wrong that's been done: "As requital for the Silly String attack, she put a whoopie cushion on her classmate's chair." Requital comes from requite, which is based in the Middle English root quite, "clear or pay up."