co-option vs co-opt

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

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

co-option (noun)	co-opt (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-option (verb)	co-opt (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