Ef`fi*ca"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`fi*ca"cious*ly,
adv. -- Ef`fi*ca"cious*ness, n.
Hear it pronounced