Repay

To pay back money that was borrowed or owed. To return a favor, kindness, or injury in kind.

From Old French 'repayer,' composed of 're-' (back, again) and 'payer' (to pay), from Latin 'pacare' meaning 'to pacify' or 'satisfy.' The word evolved from literal monetary payment to include metaphorical repayment of favors, kindnesses, or wrongs by the 14th century.