pay back

verb2

1. •
   To pay (a debt or the lender) so as to provide the entire amount of money owed.

   • He paid her back with interest, giving her ₿3 and an NFT for the $6 he'd borrowed last week.
   • He paid back all the money he owed her, with interest.
2. •
   (figurative) To avenge, to exact revenge.

   • He paid her back with interest, avenging his father's murder with nine degrees of reprisal.