store detective vs operative

store detective and operative both are nouns.

Word	Noun	Adjective	Verb	Adverb
store detective	Yes	No	No	No
operative	Yes	Yes	No	No

As nouns, operative is a hypernym of store detective; that is, operative is a word with a broader meaning than store detective:

store detective: a private detective employed by a merchant to stop pilferage
operative: someone who can be employed as a detective to collect information and assist in criminal investigations

Other hypernyms of store detective include PI, private detective, private eye, private investigator, shamus, sherlock.

store detective (noun)	operative (noun)
a private detective employed by a merchant to stop pilferage	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

store detective (adjective)	operative (adjective)
	being in force or having or exerting force
	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