formal
to make suitable return to somebody for (a benefit or service)
I should be guilty of great ingratitude if I omitted this honourable mention of her care and affection towards me, which I heartily wish it were in my power to requite as she deserves — Jonathan Swift
to compensate sufficiently for (an injury)
to make retaliation for (e.g. a wrong)
requital noun
[re- + obsolete quite to quit, pay, from Middle English quiten: see quit2]