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

Herro was inefficient on Saturday, though, finishing with 10 points on 4-of-14 shooting from the field and 2-of-8 shooting on threes. —Anthony Chiang, Miami Herald, 15 Mar. 2026

Both were prone to short, inefficient outings last season after returning from injuries, which necessitated an innings-eater out of the bullpen. —Abbey Mastracco, New York Daily News, 13 Mar. 2026

This Pi Day, consider joining in on the tradition of finding the value of pi in wildly inefficient ways. —Emma R. Hasson, Scientific American, 12 Mar. 2026

Rublev is not the first player to use his body as a highly inefficient smashing post. —James Hansen, New York Times, 10 Mar. 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