pay back vs pay off

pay back and pay off both are verbs.

Word	Noun	Adjective	Verb	Adverb
pay back	No	No	Yes	No
pay off	No	No	Yes	No

As verbs, pay back and pay off are synonyms defined as:

Other synonyms of pay back include fix, get.

pay back (verb)	pay off (verb)
take vengeance on or get even	take vengeance on or get even
act or give recompense in recognition of someone's behavior or actions	eliminate by paying off (debts)
	pay someone with influence in order to receive a favor
	yield a profit or result
	pay off (loans or promissory notes)
	do or give something to somebody in return