insufficient

adjective

in·​suf·​fi·​cient ˌin(t)-sə-ˈfi-shənt 

: not sufficient : inadequate

insufficient funds

especially : lacking adequate power, capacity, or competence

insufficient bandwidth

insufficiently adverb

Synonyms of insufficient

• lacking
• inadequate
• scarce
• low

Examples of insufficient in a Sentence

The case was thrown out because of insufficient evidence.

there's been an insufficient number of volunteers for the job, so I'll have to select someone

Recent Examples on the Web

Instead, prosecutors have pointed to sanctions policy and national security concerns — arguments the defense calls both insufficient and inconsistent. —Antonio María Delgado, Miami Herald, 20 Mar. 2026

At a 2022 civil trial in Manhattan federal court, a jury found insufficient evidence to hold Spacey liable for Rapp’s claims. —Nancy Dillon, Rolling Stone, 19 Mar. 2026

The city’s leaders worry about the facility's insufficient infrastructure. —Lautaro Grinspan, AJC.com, 18 Mar. 2026

In 2019, he was taken into custody on suspicion of homicide, but prosecutors declined to file charges, citing insufficient evidence, according to the San Francisco Examiner. —Stepheny Price, FOXNews.com, 18 Mar. 2026

Word History

Etymology

Middle English, from Anglo-French, from Late Latin insufficient-, insufficiens, from Latin in- + sufficient-, sufficiens sufficient

First Known Use

14th century, in the meaning defined above

Rhymes for insufficient

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

Kids Definition

insufficient

adjective

in·​suf·​fi·​cient ˌin(t)-sə-ˈfish-ənt 

: not sufficient : inadequate

insufficiently adverb