de·​fi·​cient | \ di-ˈfi-shənt How to pronounce deficient (audio) \

Definition of deficient

 (Entry 1 of 2)

1 : lacking in some necessary quality or element deficient in judgment bones deficient in calcium
2 : not up to a normal standard or complement (see complement entry 1 sense 1b(1)) : defective deficient strength … rusted and aging pipes … abetted by deficient maintenance and sabotage.— Adam Nossiter



Definition of deficient (Entry 2 of 2)

: a person or thing that is deficient a mental deficient

Other Words from deficient


deficiently adverb

Synonyms & Antonyms for deficient

Synonyms: Adjective

Antonyms: Adjective

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Examples of deficient in a Sentence

Adjective Several bridges in the city are structurally deficient. a diet deficient in calcium can lead to weak bones
Recent Examples on the Web: Adjective The model projected that more than half of the data-deficient species included in the analysis are threatened with extinction. Rachel Nuwer, Scientific American, 4 Aug. 2022 The monitor supplemented my port-deficient Dell XPS 13 laptop quite well. Scharon Harding, Ars Technica, 10 June 2022 All 12 participants had similar mutations in what’s called mismatch repair-deficient colorectal cancer, which occurs in about 5 to 10 percent of colorectal cancers, per the study. Margaret Osborne, Smithsonian Magazine, 8 June 2022 Is BlackRock’s $10 trillion in assets enough to engineer a self-fulfilling prophecy of a premature leap to a carbon-free but energy-deficient future? WSJ, 2 June 2022 Machines are great for transactional purposes but are deficient in relational connection. Expert Panel®, Forbes, 30 June 2022 Fifteen percent of the population are deficient in vitamin B12, for example, particularly those who practice a vegan or vegetarian diet. Dr. Michael Daignault, USA TODAY, 30 June 2022 Nearly half of Americans are deficient in the mineral, which can help ease stress and relax the body—among other benefits. Ali Francis, Bon Appétit, 21 June 2022 The Netherlands is famously deficient in something bulbs need: land. John Kelly, Washington Post, 28 June 2022 Recent Examples on the Web: Noun According to a 2010 article from the International Journal of Health Sciences, over 1 billion people worldwide are vitamin D deficient. Valerie Pavilonis, USA TODAY, 9 Feb. 2022 The best way to hide the deficient, though, is through a dominating offense which brings us back to Jackson and Roman. Mike Preston,, 5 June 2021 Some research is also starting to show that many severe COVID-19 patients are vitamin D deficient. Fedor Kossakovski, Science, 15 Dec. 2020 But rising home prices are bailing out large numbers of the equity deficient: their number is down by more than 1.2 million in the last 12 months. Kenneth R. Harney, miamiherald, 22 Aug. 2017 See More

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'deficient.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

First Known Use of deficient


1581, in the meaning defined at sense 1


1906, in the meaning defined above

History and Etymology for deficient


borrowed from Latin dēficient-, dēficiens, present participle of dēficere "to leave without enough, let down, be lacking, run short, fail," from dē- de- + facere "to make, bring about, perform, do" — more at fact


derivative of deficient entry 1

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Time Traveler for deficient

Time Traveler

The first known use of deficient was in 1581

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Dictionary Entries Near deficient

deficiency disease


deficient number

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Statistics for deficient

Last Updated

11 Aug 2022

Cite this Entry

“Deficient.” Dictionary, Merriam-Webster, Accessed 19 Aug. 2022.

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More Definitions for deficient


de·​fi·​cient | \ di-ˈfi-shənt How to pronounce deficient (audio) \

Kids Definition of deficient

: lacking something necessary for completeness or health Her diet is deficient in proteins.


de·​fi·​cient | \ di-ˈfish-ənt How to pronounce deficient (audio) \

Medical Definition of deficient

 (Entry 1 of 2)

1 : lacking in some necessary quality or element a deficient diet
2 : not up to a normal standard or complement deficient strength
3 : having, relating to, or characterized by a genetic deletion



Medical Definition of deficient (Entry 2 of 2)

: one that is deficient a mental deficient

More from Merriam-Webster on deficient

Nglish: Translation of deficient for Spanish Speakers

Britannica English: Translation of deficient for Arabic Speakers


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