efficient

efficient — adjective

1. A person, machine, or system that does a task well and quickly, using a sensible

1.adjectiveB1
Definition

A person, machine, or system that does a task well and quickly, using a sensible method and making good use of time.

Example

Sora is the most efficient worker in the kitchen — he never wastes a single movement.

efficient + noun describing a person

The new hospital filing system is far more efficient than the old paper-based one.

comparative: more efficient than

Common collocations
  • efficient worker
  • efficient service
  • efficient way
  • efficient method
  • efficient system
  • efficient operation
  • efficient at
Synonyms
  • effective

    Focuses on achieving the desired result rather than on the speed or method.

  • productive

    Emphasises a large amount of output; does not necessarily imply good organisation.

  • organized

    Describes a structured approach, but does not carry the sense of speed.

Antonyms
  • inefficient

    Wastes time or effort; opposite in both senses.

  • disorganized

    Lacks structure or order, leading to slowness.

Grammar Patterns

efficient + noun

efficient at + noun/gerund

more efficient than

Usage Note

Frequently used to describe people, processes, or systems. When describing a person's skill, the pattern efficient at + noun/gerund is standard: efficient at solving problems.

Common Mistakes

She is very efficient to finish her work.
She is very efficient at finishing her work.
'efficient' takes 'at' + gerund, not 'to' + infinitive.
He works efficient.
He works efficiently.
Use the adverb 'efficiently' to describe how an action is done.

2. Something that achieves what it is meant to do without using more fuel, water, m

2.adjectiveB1
Definition

Something that achieves what it is meant to do without using more fuel, water, money, or other resources than necessary.

Example

Modern air conditioners are much more efficient, using less electricity than older models.

efficient + using less [resource]

Élise installed an efficient shower head that cuts her water bill by half.

efficient + noun (appliance)

Common collocations
  • energy-efficient
  • fuel-efficient
  • cost-efficient
  • water-efficient
  • efficient use of
Synonyms
  • economical

    Specifically about saving money or resources; often used for vehicles and appliances.

  • resource-saving

    A more direct but less common synonym for the resource-waste sense.

Antonyms

Grammar Patterns

efficient + noun

energy-efficient / fuel-efficient

more efficient

Usage Note

Subject is typically a machine, appliance, vehicle, building, or system that consumes resources. Commonly appears in compound adjectives: energy-efficient, fuel-efficient, cost-efficient.

Common Mistakes

This car is efficient of fuel.
This car is fuel-efficient.
Use the compound form or rephrase as 'efficient in its use of fuel.'
An efficient air conditioner saves money of electricity.
An energy-efficient air conditioner saves money on electricity.
'of' is not the correct preposition after 'save' in this context.

Word family

Synonym discussion

Sense: adjective/1

Efficient, effective, productive, and organized are often confused. Efficient focuses on the process: doing something well with minimal wasted time or effort. Effective focuses on the outcome: achieving the intended result, regardless of method. Productive emphasises the amount of output — a productive person creates a lot, but may not be organised. Organized describes being arranged in a clear, logical way, but does not imply speed. For example: 'An efficient team finishes on time with few wasted steps. An effective team meets its goals. A productive team produces a high volume of work. An organized team keeps everything in its proper place.'

efficient ↗effective ↗productive ↗organized ↗

Common collocations

Nouns

Adverbs

Phrases

  • in an efficient manner
  • with efficient use of

Prepositions

Etymology

LatinFrenchEnglish

The word 'efficient' entered English from French in the 14th century, tracing back to the Latin verb 'efficere', meaning 'to work out, accomplish, produce'. This verb is a combination of 'ex-' (out) and 'facere' (to do or make). Originally a philosophical term in English ('efficient cause'), it took on its modern sense of 'productive with minimal waste' in the 18th century during the Industrial Revolution.