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

Both times, nearby neighbors sued, arguing the environmental review behind the change was insufficient and didn’t fully study the effect of taller buildings. — Zack Defazio Farrell, San Diego Union-Tribune, 31 July 2026

Sacramento County prosecutors found insufficient evidence and declined to file criminal charges against local chef and restaurateur Adam Pechal, who was arrested earlier this week on a felony domestic violence charge. — Rosalio Ahumada, Sacbee.com, 31 July 2026

Traditional cybersecurity, particularly Zero Trust's reliance on identity, is insufficient for these autonomous, ephemeral agents. — Zak Doffman, Forbes.com, 31 July 2026

Police later closed their criminal investigation after finding insufficient evidence to pursue charges. — Nora O'Neill, Charlotte Observer, 31 July 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