OPERATIVE

I. adjective Date: 15th century 1. producing an appropriate effect ; efficacious , most significant or essential , exerting force or influence ; operating , 3. having to do with physical operations (as of machines), working , based on or consisting of an operation , ~ly adverb ~ness noun II. noun Date: circa 1810 operator : as, artisan , mechanic , a secret agent, private detective , a person who works toward achieving the objectives of a larger interest