operative
1. op.er.a.tive \'a:p-(*-)r*t-iv, 'a:p-*-.ra-t-\ aj 1: producing an appropriate effect : EFFICACIOUS 2: exerting force or influence : OPERATING 3a: having to do with physical operations 3b: WORKING {an ~ craftsman} 4: based upon or consisting of an operation - op.er.a.tive.ly av 2. operative n : OPERATOR : as : ARTISAN, MECHANIC : a secret agent : private detective