Word
efficient
Phoneticsef·fi·cient, stress on the second syllable
US/ɪˈfɪʃənt/
UK/ɪfˈɪʃənt/
Definitions
01productive and organized
B2 · Upper Intermediate
adj. working in a well-organized way without wasting time or energy.
adj. performing or functioning in the best possible manner with the least waste of time and effort.
日本語:効率的※
“The new secretary is very efficient and finishes her reports much faster than the last one.”
“By reorganising the workflow, the manager created a more efficient system that reduced overtime costs by twenty percent.”
Pitfall
The new medicine is very efficient at curing the flu.
The new medicine is very effective at curing the flu.
Use 'effective' for something that produces a result, and 'efficient' for something that works without wasting resources.
Synonyms
Antonyms
02energy or resource usage
B2 · Upper Intermediate Science Technical
adj. using very little fuel, electricity, or money to do a job.
adj. relating to the ratio of useful output to the total energy or resources consumed.
日本語:効率的※
“We bought an efficient washing machine that uses less water and electricity.”
“The engineering team focused on developing a more fuel-efficient engine to meet the new environmental regulations.”
Synonyms
Antonyms
03causing an effect
C2 · Proficiency Law Formal · Technical
adj. the actual thing or person that makes something happen.
adj. acting as the immediate agent or cause that produces a specific effect or result.
“The court had to decide if the driver's actions were the efficient cause of the accident.”
“In legal theory, the efficient cause is the primary agency that sets a chain of events in motion, leading directly to the injury in question.”
Usage
Commonly found in the phrase 'efficient cause' in legal or philosophical texts.
Synonyms
Collocations
Common phrases and expressions where native English speakers use the word “efficient” in context.
Adjective
01. efficient management
“The company's success is largely due to the efficient management of its resources.”
adj + noun
02. efficient manner
“Please ensure that all customer complaints are handled in an efficient manner.”
adj + noun
03. efficient means
“Cycling is often the most efficient means of transport in a crowded city.”
adj + noun
04. efficient method
“Scientists are looking for a more efficient method of storing solar energy.”
adj + noun
05. efficient procedure
“The hospital implemented a more efficient procedure for admitting new patients.”
adj + noun
06. efficient process
“Automating the data entry created a much more efficient process for the team.”
adj + noun
07. efficient system
“The new software provides an efficient system for tracking inventory in real time.”
adj + noun
08. efficient use
“The architect focused on the efficient use of space in the small apartment.”
adj + noun
09. efficient way
10. merit efficient
Confusables
Effective means a thing works to get the job done, while efficient means it works without wasting time, money, or energy.
RememberEffective = Ends the problem. Efficient = Economical process.
Efficient is about how well a task is performed with minimal waste, while sufficient is simply about having enough of something to meet a need.
RememberEfficient = Excellence in process. Sufficient = Satisfactory in amount.
Real-World Examples
“The bio-hybrid technology could eventually help make AI systems and next-generation computers far more energy efficient.” “Meanwhile, the fridges themselves have been made more energy efficient.” “Researchers say the approach could eventually support turbines that are lighter, less expensive, and highly efficient.” “We make an inventory of 'what's in the fridge' so that we can use all these elements in the most efficient way possible.” Etymology
1398, “making,” from Old French, from Latin efficientem, nominative efficiēns, participle of efficere (“work out, accomplish”) (see effect). Meaning “productive, skilled” is from 1787. Efficiency apartment is first recorded 1930, American English.
Etymology adapted from Wiktionary, available under CC BY-SA 4.0.
Word family
NOUN
ADJECTIVE
ADVERB
- Exam level
- CambridgeCambridgeCambridge English QualificationsThe exam suite from Cambridge University Press & Assessment, from A1 Movers up to C2 Proficiency. The benchmark names double as CEFR labels.B2 FirstIELTSIELTSInternational English Language Testing SystemThe 0–9 band test co-owned by the British Council, IDP, and Cambridge. Used for university entry, work, and migration.5.5–6.5TOEFL iBTTOEFL iBTTest of English as a Foreign Language, Internet-Based TestETS's academic English test, the standard route for US university admissions. Scored 0–120, with a 1–6 scale since 2026.1–6 scale: 4.0–4.572–94TOEICTOEICTest of English for International CommunicationETS's workplace English test, big in Japan and Korea. Listening & Reading scores 10–990 and tops out at C1.785–944
- Frequency
- Common
- Level
- B2 · Upper IntermediateOxford
- Updated
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「日本語」 data: JMdict (EDRDG), CC BY-SA 4.0