rehearse vs rehearsal

rehearse is not a noun while rehearsal is a noun.

Word	Noun	Adjective	Verb	Adverb
rehearse	No	No	Yes	No
rehearsal	Yes	No	No	No

rehearse (noun)	rehearsal (noun)
	(psychology) a form of practice; repetition of information (silently or aloud) in order to keep it in short-term memory
	a practice session in preparation for a public performance (as of a play or speech or concert)

rehearse (verb)	rehearsal (verb)
engage in a rehearsal (of)