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"

• hard-hitting, trenchant — characterized by or full of force and vigor
• impelling — markedly effective as if by emotional pressure
• impressive, telling — producing a strong effect
• rough-and-ready — crude but effective for the purpose at hand

• effectiveness, effectivity, effectualness, effectuality — power to be effective; the quality of being able to bring about an effect