Efficaciter, pe. cor. Aduerb. Plin. Effectually: with effect: to some profit.
Efficax, pe. cor. huius, efficâcis, om. g. Plin. Effectual: of strength: force, or power: that can doe much.Efficacius ad rectè viuendum. Pl. iu. Of more efficacy, or force to honest life.Efficaces ad muliebre ingeniÛ preces. Li. Praiers effecteous and much preuailing with womens natures.Efficax aduersus serpentes. Plin. Contra sagittarum ictus efficacissimum. Pli. Of great force.Efficacissima auxilia. Plin. Helpes of great efficacie.Tardus & parum efficax homo. Cæl. ad Ciceronem. A slacke man and bringing little to effect, or doing, nothing effectually.Efficax vir. Hora. A valiant and strong man able to atchieue that he taketh in hand.
Lewis and Short: Latin dictionary
effĭcācĭter, adv., efficaciously, effectually, v. efficax fin.