curtail vs cut back

curtail and cut back both are verbs.

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

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

Other synonyms of curtail include curb, restrict.

curtail (verb)	cut back (verb)
place restrictions on	place restrictions on
terminate or abbreviate before its intended or proper end or its full extent	cut down on; make a reduction in
	cultivate, tend, and cut back the growth of
	return in time