efficient /(ĕf*fĭsh"ent)/

ef·fi·cient

efficient

a.
  1. 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.

Efficient

n.
  1. An efficient cause; a prime mover.
    God . . . moveth mere natural agents as an efficient only.