deficiency
Americannoun
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the state of being deficient; lack; incompleteness; insufficiency.
- Synonyms:
- scarcity, paucity, inadequacy, shortage
-
the amount lacked; a deficit.
noun
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the state or quality of being deficient
-
a lack or insufficiency; shortage
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another word for deficit
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biology the absence of a gene or a region of a chromosome normally present
Other Word Forms
Etymology
Origin of deficiency
First recorded in 1625–35; from Late Latin dēficientia, Latin dēficient- (stem of dēficiēns ); see origin at deficient, -ency
Explanation
A deficiency is an insufficient amount of something. If you feel sluggish and tired all day, you might have an iron deficiency, meaning you aren't eating enough iron-rich foods. You are most likely to hear the word deficiency in regard to health, like a sleep deficiency. But you can use deficiency to describe other kinds of lack — a deficiency of fun that occurred while your friends were out of town. Deficiency also means a failure or shortcoming, like a deficiency in math class, which might result in a notice from school — known as a deficiency — being mailed to your home.
Vocabulary lists containing deficiency
Freak the Mighty
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Flowers for Algernon
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Paltry Parlance: Synonyms for "Few"
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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.
"Revisiting the definition of B12 deficiency to incorporate functional biomarkers could lead to earlier intervention and prevention of cognitive decline."
From Science Daily • May 22, 2026
The minimum threshold used to define deficiency may not capture early functional changes in the nervous system.
From Science Daily • May 22, 2026
B12 is clearly essential for the nervous system, and deficiency should not be ignored.
From Science Daily • May 22, 2026
Patients with vitamin D deficiency were three times more likely to experience moderate to severe pain during the first 24 hours after surgery compared with patients who had adequate vitamin D levels.
From Science Daily • May 20, 2026
Cruelly, callously, admissions committees agreed to overlook serious academic deficiency.
From "Hunger of Memory" by Richard Rodriguez
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
