set back vs scrub

set back is not a noun while scrub is a noun.

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

set back (noun)	scrub (noun)
	the act of cleaning a surface by rubbing it with a brush and soap and water
	dense vegetation consisting of stunted trees or bushes

set back (adjective)	scrub (adjective)
	(of domestic animals) not selectively bred

set back (verb)	scrub (verb)
slow down the progress of; hinder	wash thoroughly
cost a certain amount	clean with hard rubbing
hold back to a later time	postpone indefinitely or annul something that was scheduled