'payback' definitions:

Financial return or reward (especially returns equal to the initial investment)

The act of taking revenge (harming someone in retaliation for something harmful that they have done) especially in the next life; "Vengeance is mine; I will repay, saith the Lord"-- Romans 12:19; "For vengeance I would do nothing. This nation is too great to look for mere revenge"--James Garfield; "he swore vengeance on the man who betrayed him"; "the swiftness of divine retribution" [syn: vengeance, retribution, payback]