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Synonyms

insufficient

American  
[in-suh-fish-uhnt] / ˌɪn səˈfɪʃ ənt /

adjective

  1. not sufficient; lacking in what is necessary or required.

    an insufficient answer.

    Synonyms:
    deficient, scanty, inadequate
  2. deficient in force, quality, or amount; inadequate.

    insufficient protection.


insufficient British  
/ ˌɪnsəˈfɪʃənt /

adjective

  1. not sufficient; inadequate or deficient

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Other Word Forms

  • insufficiently adverb

Etymology

Origin of insufficient

First recorded in 1350–1400; Middle English, from Late Latin insufficient-, stem of insufficiēns; equivalent to in- 3 + sufficient

Explanation

If something is insufficient, it isn't enough. A high school diploma is very helpful for getting a job, but by itself, it's probably insufficient to land you a job as an astronaut. Something adequate is sufficient, and something inadequate is insufficient (in- meaning "not"). If you have $100 in the bank and you try to use a debit card for a $102 purchase, even though you’re close to having enough, your funds are insufficient to cover the sale. Anything that falls short of a required amount or expected measure is insufficient, whether it's the amount of air in a bike tire or the votes needed to win an election.

Keep Reading on Vocabulary.com

Vocabulary lists containing insufficient

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

Ships transiting the strait were also excluded where there was insufficient data that they followed the Larak route.

From The Wall Street Journal • Apr. 11, 2026

The investigation was closed in 2019 after prosecutors decided there was insufficient evidence to bring charges.

From BBC • Apr. 8, 2026

He contended that the evidence at trial was insufficient to sustain the conviction or to show that the proper venue for the trial was Texas.

From Los Angeles Times • Apr. 7, 2026

On Monday, he said a temporary ceasefire proposal being circulated was insufficient.

From Barron's • Apr. 7, 2026

As Venkatesh would later tell his university colleagues, he realized that the multiple-choice answers A through E were insufficient.

From "Freakonomics: A Rogue Economist Explores the Hidden Side of Everything" by Steven D. Levitt