inefficient

inefficient — adjective

1. not capable of doing a job well because of poor methods, lack of organisation, o

1.adjectiveB2
Definition

not capable of doing a job well because of poor methods, lack of organisation, or limited ability — a person, a way of working, or a system can be described this way.

Example

Mert was fired because his inefficient methods doubled the team's workload every week.

collocation: inefficient methods / inefficient system

Yan found that the inefficient filing system made simple tasks take twice as long.

Common collocations
  • inefficient worker
  • inefficient method
  • inefficient system
  • inefficient process
  • hopelessly inefficient
  • inefficient at [doing something]
Synonyms
  • ineffective

    focuses on not achieving the desired result at all, whereas inefficient emphasises wasted effort even if the result is eventually reached

  • incompetent

    stronger and more personal — implies a fundamental lack of skill rather than poor method choices

  • unproductive

    highlights low output rather than the quality of the method used

Antonyms
  • efficient

    achieves results with minimal wasted time or effort

  • productive

    produces good results in relation to the effort invested

Grammar Patterns

inefficient + noun

inefficient at/in + noun/gerund

Usage Note

Subject is usually a person, method, or organisation, not a machine or technical device. For equipment that wastes energy or fuel, see sense 2.

Common Mistakes

He is inefficient of managing projects.
He is inefficient at managing projects.
the adjective takes 'at' or 'in', not 'of'.
The machine is inefficient about energy.
The machine is inefficient in its use of energy.
use 'in' followed by a noun phrase describing the area of inefficiency.

2. using more time, money, fuel, or other resources than necessary to achieve a res

2.adjectiveB2
Definition

using more time, money, fuel, or other resources than necessary to achieve a result — describes equipment, processes, or systems that consume too much of something valuable.

Example

Nikhil replaced his old inefficient water heater with a new solar-powered model.

inefficient [appliance] — wastes energy

The factory's inefficient use of raw materials was costing them thousands every month.

Common collocations
  • inefficient use of [resources]
  • inefficient engine / boiler / heater
  • energy-inefficient
  • grossly inefficient
  • inefficient in its use of [fuel, water, energy]
Synonyms
  • wasteful

    broader — can describe any unnecessary consumption, while inefficient often carries a sense of poor design or mechanics

  • uneconomical

    specifically about money or cost — an inefficient engine may also be uneconomical to run

  • wasteful of

    followed directly by the resource being wasted, e.g. wasteful of energy

Antonyms
  • efficient

    achieves a result with minimal waste of resources

  • energy-efficient

    a specific, common compound antonym for appliances and buildings

Grammar Patterns

inefficient + noun

inefficient in its use of + noun

Usage Note

Subject is typically a device, piece of equipment, or industrial process. The criticism is about how much of a resource is consumed, not about the skill or ability of a person.

Common Mistakes

This engine is very inefficient of petrol.
This engine is very inefficient
it uses too much petrol.' — do not introduce the wasted resource with 'of'; state the inefficiency and then explain what is wasted in a separate clause.

Word family

Synonym discussion

Sense: adjective/1

All four words describe someone or something that falls short of expected performance, but each has a different focus. Ineffective means not producing the intended result at all — a medicine can be ineffective, but you would not call it incompetent. Incompetent is more personal and severe, implying a fundamental lack of necessary skill or knowledge. Unproductive focuses on low output relative to input, often used for meetings, farmland, or workers. Inept suggests clumsiness or awkwardness in action — an inept salesperson handles customers poorly. A manager could be inefficient (slow, poorly organised) without being incompetent (entirely unqualified). In everyday use, inefficient is the mildest of the four.

ineffective ↗incompetent ↗unproductive ↗inept

Common collocations

Adverbs

  • highly inefficient
  • grossly inefficient
  • terribly inefficient
  • hopelessly inefficient

Phrases

  • inefficient use of [time/money/resources]

Prepositions

  • inefficient at [something]
  • inefficient in [something]

Etymology

LatinFrenchEnglish

Formed in English from the prefix 'in-' (meaning 'not') and 'efficient', which comes from Latin 'efficientem' — the present participle of 'efficere', meaning 'to accomplish, produce, or bring about'. The word entered English usage around the mid-18th century, originally describing actions that fail to produce the intended effect.