Operative

Webster's Dictionary of the English Language

·adj Based upon, or consisting of, an operation or operations; as, operative surgery.

II. Operative ·noun A skilled worker; an artisan; ·esp., one who operates a machine in a mill or manufactory.

III. Operative ·adj Producing the appropriate or designed effect; efficacious; as, an operative dose, rule, or penalty.

IV. Operative ·adj Having the power of acting; hence, exerting force, physical or moral; active in the production of effects; as, an operative motive.