revenge vs payback

revenge and payback both are nouns.

Word	Noun	Adjective	Verb	Adverb
revenge	Yes	No	Yes	No
payback	Yes	No	No	No

As nouns, payback is a hyponym of revenge; that is, payback is a word with a more specific, narrower meaning than revenge:

revenge: action taken in return for an injury or offense
payback: the act of taking revenge (harming someone in retaliation for something harmful that they have done) especially in the next life

Other hyponyms of revenge include retribution, vengeance, reprisal.

revenge (noun)	payback (noun)
action taken in return for an injury or offense	the act of taking revenge (harming someone in retaliation for something harmful that they have done) especially in the next life
	financial return or reward (especially returns equal to the initial investment)

revenge (verb)	payback (verb)
take revenge for a perceived wrong