Definition of "efficient" []

• Acting directly to produce an effect: an efficient cause. See Synonyms at effective. (adjective)
• Acting or producing effectively with a minimum of waste, expense, or unnecessary effort. (adjective)
• Exhibiting a high ratio of output to input. (adjective)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "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."
• "[37] 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."