cut back vs subtract

cut back and subtract both are verbs.

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

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

cut back (verb)	subtract (verb)
place restrictions on	take off or away
cut down on; make a reduction in	make a subtraction
cultivate, tend, and cut back the growth of
return in time