efficacious -
marked by qualities giving the power to produce an intended effect; "written propaganda is less efficacious than the habits and prejudices...of the readers"-Aldous Huxley; "the medicine is efficacious in stopping a cough"
inefficacious lacking the power to produce a desired effect; "laws that are inefficacious in stopping crime"
effectual,
efficacious,
effective marked by qualities giving the power to produce an intended effect; "written propaganda is less efficacious than the habits and prejudices...of the readers"-Aldous Huxley; "the medicine is efficacious in stopping a cough"
efficaciousness,
efficacy capacity or power to produce a desired effect; "concern about the safety and efficacy of the vaccine"
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"
uneffective,
ineffective,
ineffectual lacking the ability or skill to perform effectively; inadequate; "an ineffective administration"; "inefficient workers"
efficacious marked by qualities giving the power to produce an intended effect; "written propaganda is less efficacious than the habits and prejudices...of the readers"-Aldous Huxley; "the medicine is efficacious in stopping a cough"
efficient being effective without wasting time or effort or expense; "an efficient production manager"; "efficient engines save gas"
potent,
stiff,
strong having a strong physiological or chemical effect; "a potent toxin"; "potent liquor"; "a potent cup of tea", "a stiff drink"
powerful having great power or force or potency or effect; "the most powerful government in western Europe"; "his powerful arms"; "a powerful bomb"; "the horse's powerful kick"; "powerful drugs"; "a powerful argument"
utile,
useful being of use or service; "the girl felt motherly and useful"; "a useful job"; "a useful member of society"
