operative vs in operation

operative is a noun but in operation is not a noun.

Word	Noun	Adjective	Verb	Adverb
operative	Yes	Yes	No	No
in operation	No	Yes	No	No

operative (noun)	in operation (noun)
someone who can be employed as a detective to collect information and assist in criminal investigations
a person secretly employed in espionage for a government

operative (adjective)	in operation (adjective)
being in force or having or exerting force	being in effect or operation
relating to or requiring or amenable to treatment by surgery especially as opposed to medicine
(of e.g. a machine) performing or capable of performing
effective; producing a desired effect