refutation vs rebuttal

refutation and rebuttal both are nouns.

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

As nouns, rebuttal is a hyponym of refutation; that is, rebuttal is a word with a more specific, narrower meaning than refutation:

refutation: the speech act of answering an attack on your assertions
rebuttal: the speech act of refuting by offering a contrary contention or argument

Other hyponyms of refutation include confutation.

refutation (noun)	rebuttal (noun)
the act of determining that something is false	the speech act of refuting by offering a contrary contention or argument
any evidence that helps to establish the falsity of something	(law) a pleading by the defendant in reply to a plaintiff's surrejoinder
the speech act of answering an attack on your assertions