repay

Concise Oxford English Dictionary © 2008 Oxford University Press:
repay/rɪˈpeɪ/

▶verb (past and past part. repaid)

• 1 pay back (a loan).

  ■ pay back money owed to (someone).

• 2 do or give something as recompense for (a favour or kindness received).

• 3 Brit. be worth devoting time to (a specified action).

– derivatives
repayable adjective,
repayment noun.