knock back vs set back

knock back and set back both are verbs.

Word	Noun	Adjective	Verb	Adverb
knock back	No	No	Yes	No
set back	No	No	Yes	No

As verbs, knock back and set back are synonyms defined as:

Other synonyms of knock back include put back.

knock back (verb)	set back (verb)
cost a certain amount	slow down the progress of; hinder
	cost a certain amount
	hold back to a later time