operative

nouns

a person secretly employed in espionage for a government
someone who can be employed as a detective to collect information

adjectives

being in force or having or exerting force
"operative regulations"; "the major tendencies operative in the American political system"
antonym
is similar to
having influence or producing an effect
"many emotional determinants at work"; "an operant conscience"
is similar to
exerting force or influence
"the law is effective immediately"; "a warranty good for two years"; "the law is already in effect (or in force)"
is similar to
being in effect or operation
"de facto apartheid is still operational even in the `new' African nations"- Leslie Marmon Silko; "bus service is in operation during the emergency"; "the company had several operating divisions"
is similar to
serving to permit or facilitate further work or activity
"discussed the working draft of a peace treaty"; "they need working agreements with their neighbor states on interstate projects"
relating to or requiring or amenable to treatment by surgery especially as opposed to medicine
"a surgical appendix"; "a surgical procedure"; "operative dentistry"
is derived from
is derived from
effective; producing a desired effect
"the operative word"
is similar to
important in effect or meaning
"a significant change in tax laws"; "a significant change in the Constitution"; "a significant contribution"; "significant details"; "statistically significant"
(of e.g. a machine) performing or capable of performing
"in running (or working) order"; "a functional set of brakes"
is derived from
is derived from