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

Too quickly, and the exposure would be insufficient. —Kaif Shaikh, Interesting Engineering, 23 Dec. 2025

But even taken together, these reasons are insufficient. —Literary Hub, 23 Dec. 2025

When the wind is insufficient, propulsion will come from two retractable electric-drive propellers that draw power from the 580 kWh battery bank. —Michael Verdon, Robb Report, 20 Dec. 2025

They were charged with violating local noise rules, but the city prosecutor later declined to pursue charges due to insufficient evidence about who was making the noise. —Nandika Chatterjee, Time, 19 Dec. 2025

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