English Reference
adjective · noun

inefficient

adj. · n.
US /ˌɪnɪˈfɪʃənt/ UK /ɪnɪfˈɪʃənt/ in·ef·fi·cient

  1. 01 B2 Upper Intermediate

    adj.not using time, money, or energy in the best way.

    adj.failing to make the best use of time or resources; wasteful in operation or process.

    Simple

    The old heating system is very inefficient and costs a lot to run.

    In context

    The audit revealed that the current supply chain is highly inefficient, resulting in significant overhead costs and frequent delivery delays.

  2. 02 B2 Upper Intermediate

    adj.not able to do a job well because of a lack of skill or being lazy.

    adj.lacking the ability or disposition to perform a task effectively; habitually unproductive.

    Simple

    The manager was fired because he was inefficient and never finished his reports.

    In context

    The department struggled under an inefficient supervisor who failed to delegate tasks or provide clear instructions to the junior staff.

  3. 03 C2 Proficiency Formal

    n.a person who does not work well or wastes time.

    n.a person who fails to perform work or duties with the expected level of productivity.

    Simple

    The company tried to retrain the inefficients before considering layoffs.

    In context

    The historical report criticised the administration for failing to remove the inefficients who had occupied senior bureaucratic positions for decades.

    slackerunderperformer

After years of underinvestment the service is also highly inefficient.

The Guardian· 9 Aug 2026

There was criticism that they were underfunded and inefficient.

BBC News· 12 Aug 2026

From in- + efficient.

Etymology adapted from Wiktionary, available under CC BY-SA 4.0.

This entry
Level B2 · Upper Intermediate
Frequency Frequent
Updated