revenge vs get back

revenge is a noun but get back is not a noun.

Word	Noun	Adjective	Verb	Adverb
revenge	Yes	No	Yes	No
get back	No	No	Yes	No

As verbs, get back is a hyponym of revenge; that is, get back is a word with a more specific, narrower meaning than revenge:

Other hyponyms of revenge include get even.

revenge (noun)	get back (noun)
action taken in return for an injury or offense

revenge (verb)	get back (verb)
take revenge for a perceived wrong	take revenge or even out a score
	recover something or somebody that appeared to be lost
	get one's revenge for a wrong or an injury