bào yuàn
to pay back a score
to get revenge
to requite
(old) variant of 抱怨[bao4 yuan4]
yǐ dé bào yuàn
to return good for evil (idiom)
to requite evil with good
yǐ zhí bào yuàn , yǐ dé bào dé
to repay kindness with kindness, and repay enmity with justice (idiom, from Analects)