cut back vs prune

cut back is not a noun while prune is a noun.

Word	Noun	Adjective	Verb	Adverb
cut back	No	No	Yes	No
prune	Yes	No	Yes	No

As verbs, cut back and prune are synonyms defined as:

Other synonyms of cut back include clip, crop, dress, lop, snip, trim.

cut back (noun)	prune (noun)
	dried plum

cut back (verb)	prune (verb)
place restrictions on	weed out unwanted or unnecessary things
cut down on; make a reduction in	cultivate, tend, and cut back the growth of
cultivate, tend, and cut back the growth of
return in time