operative vs significant

operative is a noun but significant is not a noun.

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

operative (noun)	significant (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)	significant (adjective)
being in force or having or exerting force	important in effect or meaning
relating to or requiring or amenable to treatment by surgery especially as opposed to medicine	too closely correlated to be attributed to chance and therefore indicating a systematic relation
(of e.g. a machine) performing or capable of performing	of considerable importance, size, or worth
effective; producing a desired effect	rich in significance or implication