Ef‐fi″cient (–ent), a. [L. efficiens, -entis, p. pr. of efficere to effect: cf. F. efficient. See Effect, n.] Causing effects; producing results; that makes the effect to be what it is; actively operative; not inactive, slack, or incapable; characterized by energetic and useful activity; as, an efficient officer, power.
The efficient cause is the working cause. Wilson.
Syn. — Effective; effectual; competent; able; capable; material; potent.