improve vs improvement

improve is not a noun while improvement is a noun.

Word	Noun	Adjective	Verb	Adverb
improve	No	No	Yes	No
improvement	Yes	No	No	No

improve (noun)	improvement (noun)
	the act of improving something
	a change for the better; progress in development
	a condition superior to an earlier condition

improve (verb)	improvement (verb)
get better
to make better