effectual (
http://definr.com/effectual)
adj 1: sufficient to produce a result; "a man to whom painting was
but another and less effectual way of writing dramas
or novels or history" [ant:
ineffectual]
2: 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" [syn:
effective,
efficacious] [ant:
ineffective]
3: exerting or capable of exerting strong physiological or
chemical effects; "an effectual vaccine"