from The American Heritage® Dictionary of the English Language, 4th Edition
- adj. Acting directly to produce an effect: an efficient cause. See Synonyms at effective.
- adj. Acting or producing effectively with a minimum of waste, expense, or unnecessary effort.
- adj. Exhibiting a high ratio of output to input.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- adj. Making good, thorough, or careful use of resources; not consuming extra. Especially, making good use of time or energy.
- adj. Using a particular proportion of available energy.
from the GNU version of the Collaborative International Dictionary of English
- adj. 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.
- n. An efficient cause; a prime mover.
from The Century Dictionary and Cyclopedia
- Producing outward effects; of a nature to produce a result; active; causative.
- Acting or able to act with due effect; adequate in performance; bringing to bear the requisite knowledge, skill, and industry; capable; competent: as, an efficient workman, director, or commander.
- Synonyms Efficacious, Effectual, etc. (see effective); energetic, operative, active, ready, helpful.
- n. An efficient cause (see above).
- n. One who is efficient or qualified; specifically, in the volunteer service of Great Britain, one who has attended the requisite number of drills, and in respect of whom the corps receives the capitation grant paid by government.
- n. In mathematics, a quantity multiplied by another quantity to produce the quantity of which it is said to be an efficient; a factor.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- adj. able to accomplish a purpose; functioning effectively
- adj. being effective without wasting time or effort or expense
If he left the "road" and became a _very_ efficient common laborer, some _ordinarily efficient_ common laborer would have to take to the "road."
Now, when the advocates of free-agency insist that motive is not the efficient cause of volition, and that mind is the efficient cause thereof, we suppose them to employ the expression, _efficient cause_, in one and the same sense in both branches of the proposition.
 I use the term efficient in a technical sense, as meaning all-sufficient to produce the given effect, without the intervention of any other cause.
That isn't to deny that a war with tens of thousands of people doesn't have a significant administrative overhead; rather, that focusing on this overhead (which laughs at the term efficient) ends up seriously degrading our ability to actually achieve victory.
Sure, the critique depends on misinterpreting what the word "efficient" means, as in the "efficient markets hypothesis."
All we need to do to make the health care system cheaper and more efficient is to remove the dilution of responsibility and cost, thus rewarding people who eat right, stay healthy, and live risk-averse lives.
Investing in efficient and clean energy creates jobs in manufacturing, sales, installation, and servicing of wind turbines, solar panels, and super efficient buildings.
If you believe in efficient markets you should also believe in the toothfairy.
If you believe in efficient markets, then you should be very skeptical of the rest of this post.
How efficient is it in transporting gun, hunter, and game out of the woods that may be hilly, have rough terrain, etc