inefficient

adjective

in·​ef·​fi·​cient ˌi-nə-ˈfi-shənt 

: not efficient: such as

a

: wasteful of time or energy

inefficient operating procedures

b

: incapable, incompetent

an inefficient worker

c

: not producing the effect intended or desired

used inefficient measures

inefficient noun

inefficiently adverb

Synonyms of inefficient

• unsuccessful
• ineffective
• counterproductive

Examples of inefficient in a Sentence

The delivery system was very inefficient.

an inefficient use of fuel

Recent Examples on the Web

Changes to fiscal policies so that the government does not continue bailing out inefficient state enterprises. —Nora Gámez Torres, Miami Herald, 12 June 2026

In reality, inefficient data management drives unnecessary scale. —Expert Panel®, Forbes.com, 12 June 2026

This can be especially effective if your home has old, inefficient windows. —Kamron Sanders, Better Homes & Gardens, 11 June 2026

The reality is that the chemical reactions that comprise photosynthesis and sugar production — the foundation of life’s diet, and thus humanity’s — are highly inefficient. —Quanta Magazine, 10 June 2026

Word History

First Known Use

1750, in the meaning defined above

Rhymes for inefficient

• beneficent
• coefficient
• insufficient
• deficient
• efficient
• omniscient
• proficient
• sufficient

Kids Definition

inefficient

adjective

in·​ef·​fi·​cient ˌin-ə-ˈfish-ənt 

1

: not producing the effect expected or desired

inefficient regulations

2

: wasteful of time or energy

inefficient procedures

especially : accomplishing little relative to the time spent or effort expended

an inefficient worker

inefficiently adverb