co-opt vs co-option

co-opt is not a noun while co-option is a noun.

Word	Noun	Adjective	Verb	Adverb
co-opt	No	No	Yes	No
co-option	Yes	No	No	No

co-opt (noun)	co-option (noun)
	the selection of a new member (usually by a vote of the existing membership)
	the act of appointing summarily (with or without the appointee's consent)

co-opt (verb)	co-option (verb)
take or assume for one's own use
appoint summarily or commandeer
choose or elect as a fellow member or colleague
neutralize or win over through assimilation into an established group