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

If the season ends with insufficient snow, that creates problems for water supplies and increases the risk of wildfires when the weather warms. —Doha Madani, NBC news, 16 Feb. 2026

Democrats say Republicans' proposals to reform immigration enforcement tactics are insufficient. —Brittney Melton, NPR, 16 Feb. 2026

Rates of conditions like heart disease, cancer, diabetes and hypertension are climbing across the region, driven by insufficient exercise, poor diet, drinking, smoking, stress and pollution. —Stuart A. Spencer, Fortune, 15 Feb. 2026

Disease is caused by miasma, insufficient beef tallow, corn syrup, the evil eye. —Alexandra Petri, The Atlantic, 14 Feb. 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