[op.er.a.tive] adj (15c) 1: producing an appropriate effect: efficacious
2: exerting force or influence: operating 3 a: having to do with physical operations (as of machines) b: working "an ~ craftsman"
4: based on or consisting of an operation "~ dentistry" -- op.er.a.tive.ly adv -- op.er.a.tive.ness n
[2]operative n (ca. 1810): operator: as a: artisan, mechanic b: a secret agent c: private detective