effective, effectual, efficacious -- (producing or capable of producing an intended result or having a striking effect; "an air-cooled motor was more effective than a witch's broomstick for rapid long-distance transportation"-LewisMumford; "effective teaching methods"; "effective steps toward peace"; "made an effective entrance"; "his complaint proved to be effectual in bringing action"; "an efficacious law")
legal, sound, effectual -- (having legal efficacy or force; "a sound title to the property")
(Sound)
