[1] : The Collaborative International Dictionary of English v.0.48

efficacious \ef`fica"cious\, a. l. eficax, -acis, fr.
   efficere. see effect, n.
   possessing the quality of being effective; productive of, or
   powerful to produce, the effect intended; as, an efficacious
   law.

   syn: see effectual. -- ef`fica"ciously, adv.
        1913 webster
see also:
effect effectual ef`fica"ciously 

[2] : WordNet (r) 2.0

efficacious
     adj 1: 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" ant: inefficacious
     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, effectual ant: ineffective
see also:
inefficacious effective effectual ineffective 

[3] : Moby Thesaurus II by Grady Ward, 1.0

44 moby thesaurus words for "efficacious":
   able, active, adequate, authoritative, capable, charismatic,
   charming, competent, consequential, effective, effectual,
   efficient, enchanting, equal to, estimable, functional, go,
   important, influential, magnetic, momentous, operational,
   operative, personable, persuasive, potent, powerful, practical,
   prestigious, productive, proficient, puissant, reputable,
   serviceable, strong, suasive, substantial, successful, telling,
   up to, useful, virtuous, weighty, winning

Efficacious >> E Words
Efficacious, definition of term: Efficacious
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