deficiency

American  

[dih-fish-uhn-see] / dɪˈfɪʃ ən si /

Obsolete, deficience

noun

deficiencies plural

1. the state of being deficient; lack; incompleteness; insufficiency.

   Synonyms:

   scarcity, paucity, inadequacy, shortage

2. the amount lacked; a deficit.

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deficiency British  

/ dɪˈfɪʃənsɪ /

noun

1. the state or quality of being deficient

2. a lack or insufficiency; shortage

3. another word for deficit

4. biology the absence of a gene or a region of a chromosome normally present

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Other Word Forms

Derived Forms

• nondeficiency
  noun
• predeficiency
  noun

Inflected Forms

Nouns

• deficiencies
  plural

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.

Example Sentences

See Examples For:

deficiency deficiencies

The Pentagon plans to screen soldiers for testosterone deficiency as Defense Secretary Pete Hegseth continues his revamp of the country’s military.

From The Wall Street Journal ● Jul. 15, 2026

These symptoms are not specific to B12 deficiency, so persistent tiredness, tingling or balance problems should be checked rather than assumed to be a simple vitamin problem.

From Science Daily ● Jun. 25, 2026

Rajan takes vitamin D, a prebiotic, protein, fibre and creatine - in what he describes as a "supplement stack" - to target areas where he could have a deficiency.

From BBC ● Jun. 20, 2026

The drug was approved to treat lipoprotein lipase deficiency, a rare genetic disorder that prevents the body from properly breaking down fat particles in the blood.

From Barron's ● Jun. 17, 2026

Where there are fewer, the deficiency may be remedied by collecting and distributing the baglike cocoons containing the eggs.

From "Silent Spring" by Rachel Carson

Recent amendments to be considered include assessing a kindergartner’s math knowledge rather than screening for math deficiencies, something that would help identify students who need additional support.

From Los Angeles Times ● Jun. 30, 2026

"The investigation, prosecution, and trial of Bilal Mohammed and Yusufu Mieraili have been rife with human rights violations and have exposed some of the systemic deficiencies of Thailand's criminal justice system."

From BBC ● Jun. 11, 2026

But targeted use of vitamin D, vitamin B12, folate and, in some cases, a multivitamin or protein supplement can help when deficiencies or low intake are present.

From Science Daily ● Jun. 6, 2026

Similar treatments for the enzyme deficiencies known as Sanfilippo, Pompe and Gaucher diseases are in early clinical trials, or soon will be.

From Barron's ● Jun. 3, 2026

Santa made a sign for Mrs. Reilly not to discuss her deficiencies, but Mrs. Reilly was not to be silenced.

From "A Confederacy of Dunces" by John Kennedy Toole

Related Words

• dearth
• defect
• failing
• failure
• fault
• flaw
• frailty
• glitch
• insufficiency
• lack
• scarcity
• shortage
• shortcoming
• weakness