Definitions
1.nounAn employee or other worker with some particular function or skill.
2.nounA spy, secret agent, or detective.
3.nounA participant in an operation.
4.adjectiveEffectual or important."He's usually in a good mood — the operative word there being "usually". Today was a disaster."
5.adjectiveFunctional, in working order.
6.adjectiveHaving the power of acting; hence, exerting force, physical or moral; active in the production of effects."an operative motive"
7.adjectiveProducing the appropriate or designed effect; efficacious."an operative dose, rule, or penalty"
8.adjectiveBased upon, or consisting of, a surgical operation or operations."operative surgery"