rebut vs rebuttal

rebut is not a noun while rebuttal is a noun.

Word	Noun	Adjective	Verb	Adverb
rebut	No	No	Yes	No
rebuttal	Yes	No	No	No

rebut (noun)	rebuttal (noun)
	the speech act of refuting by offering a contrary contention or argument
	(law) a pleading by the defendant in reply to a plaintiff's surrejoinder

rebut (verb)	rebuttal (verb)
prove to be false or incorrect
overthrow by argument, evidence, or proof