recusation vs recuse

recusation is a noun but recuse is not a noun.

Word	Noun	Adjective	Verb	Adverb
recusation	Yes	No	No	No
recuse	No	No	Yes	No

recusation (noun)	recuse (noun)
(law) the disqualification of a judge or jury by reason of prejudice or conflict of interest; a judge can be recused by objections of either party or judges can disqualify themselves
(law) an objection grounded on the judge's relationship to one of the parties

recusation (verb)	recuse (verb)
	challenge or except to a judge as being incompetent or interested, in canon and civil law
	disqualify oneself (as a judge) in a particular case