operative vs preoperative

operative is a noun but preoperative is not a noun.

Word	Noun	Adjective	Verb	Adverb
operative	Yes	Yes	No	No
preoperative	No	Yes	No	No

operative (noun)	preoperative (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)	preoperative (adjective)
being in force or having or exerting force	happening or done before and in preparation for a surgical 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