naming vs co-option

naming and co-option both are nouns.

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

As nouns, co-option is a hyponym of naming; that is, co-option is a word with a more specific, narrower meaning than naming:

naming: the act of putting a person into a non-elective position
co-option: the act of appointing summarily (with or without the appointee's consent)

Other hyponyms of naming include nomination, co-optation, delegacy, ordinance, ordination, recognition.

naming (noun)	co-option (noun)
the act of putting a person into a non-elective position	the selection of a new member (usually by a vote of the existing membership)
the verbal act of naming	the act of appointing summarily (with or without the appointee's consent)

naming (adjective)	co-option (adjective)
inclined to or serving for the giving of names