cut back vs knock off

cut back and knock off both are verbs.

Word	Noun	Adjective	Verb	Adverb
cut back	No	No	Yes	No
knock off	No	No	Yes	No

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

cut back (verb)	knock off (verb)
place restrictions on	stop pursuing or acting
cut down on; make a reduction in	get rid of (someone who may be a threat) by killing
cultivate, tend, and cut back the growth of	write quickly
return in time	take by theft
	cut the price of