efficient

adjective

ef·​fi·​cient i-ˈfi-shənt 

1

: productive of desired effects

especially : capable of producing desired results with little or no waste (as of time or materials)

an efficient worker

efficient machinery

2

: being or involving the immediate agent in producing an effect

the efficient action of heat in changing water to steam

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Comparing Efficient, Effective, and Proficient

These three words cover some overlapping territory.

Efficient most often describes what is capable of producing desired results without wasting materials, time, or energy. While the word can be applied to both people and things, it is far more commonly applied to things, such as machines, systems, processes, and organizations. The focus of the word is on how little is wasted or lost while the desired results are produced.

Effective typically describes things—such as policies, treatments, arguments, and techniques—that do what they are intended to do. People can also be described as effective when they accomplish what they set out to accomplish, but the word is far more often applied to things.

Proficient typically describes people, and it often is followed by the preposition at. If you are proficient at something, you are very good at it. You are, in fact, so good at doing it that you are unusually efficient when you do it. One can also be proficient in something, such as a language.

Synonyms

• effective
• effectual
• efficacious
• fruitful
• operative
• potent
• productive

Choose the Right Synonym for efficient

effective, effectual, efficient, efficacious mean producing or capable of producing a result.

effective stresses the actual production of or the power to produce an effect.

an effective rebuttal

effectual suggests the accomplishment of a desired result especially as viewed after the fact.

the measures to stop the pilfering proved effectual

efficient suggests an acting or a potential for action or use in such a way as to avoid loss or waste of energy in effecting, producing, or functioning.

an efficient small car

efficacious suggests possession of a special quality or virtue that gives effective power.

a detergent that is efficacious in removing grease

Examples of efficient in a Sentence

Like a page-turner of a novel, [Nomar] Garciaparra keeps you eager to see what comes next, especially this season, when he will have the most efficient RBI machine in baseball, free-agent signee Manny Ramirez, riding shotgun with him. —Tom Verducci, Sports Illustrated, 5 Mar. 2001

Short and muscular, he is as efficient as a surgeon, cracking eggs with one hand and tossing the shells into the basket under the counter behind him without looking, flipping bread into the slots of a row of toasters, and literally throwing "to go" orders ten feet down the counter to the guy manning the cash register. —Paul Baumann, Commonweal, 18 July 1997

Wilde was wearing two emeralds, … one on the little finger of each hand. That on the left was the efficient cause of all joys, that on the right of misfortunes. Asked why he continued to wear the one on the right, Wilde said, "One needs misfortunes to live happily." —Richard Ellmann, Oscar Wilde, (1984) 1988

Originally designed for the preparation of desserts, the woks eventually proved their versatility as efficient vessels for stir-frying, deep-frying, and the reduction of liquids. —Kemp Miles Minifie, Gourmet, November 1988

that manual lawn mower is not a very efficient tool for doing a huge yard

Recent Examples on the Web

Future Perfect Explore the big, complicated problems the world faces and the most efficient ways to solve them. —Jess Craig, Vox, 17 Feb. 2025

Seniors Taylor Jones and Rori Harmon are excellent on the defensive end, and junior Kyla Oldacre is a quick, efficient bucket off the bench. —Steven Louis Goldstein, The Athletic, 16 Feb. 2025

Building an efficient data analytics system becomes especially important in rapidly changing environments, such as finance and investment. —Alexandra Harbert, USA TODAY, 15 Feb. 2025

The emergence of cheaper and more efficient AI models off the back of China’s DeepSeek could reshape demand for data centers, boosting a sector that investors were already heavily betting would continue to boom. —April Roach, CNBC, 14 Feb. 2025

Word History

Etymology

Middle English, "active, immediate (of a cause)," borrowed from Middle French & Latin; Middle French, borrowed from Latin efficient-, efficiens "producing or giving rise to something, immediate (of a cause), active," from present participle of efficere "to make, bring about, produce, carry out" — more at effect entry 1

First Known Use

14th century, in the meaning defined at sense 2

Phrases Containing efficient

• cost-efficient
• hyper-efficient

Kids Definition

efficient

adjective

ef·​fi·​cient i-ˈfish-ənt 

: capable of producing desired results especially without waste (as of time or energy)

an efficient worker

efficient machinery

efficiently adverb