n. An efficient cause; a prime mover. [ 1913 Webster ]
God . . . moveth mere natural agents as an efficient only. Hooker. [ 1913 Webster ]
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;
The efficient cause is the working cause. Wilson.
adv. With effect; effectively. [ 1913 Webster ]