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 lower concentration can cause nutrient deficiency, coupled with the reduced ability of the baby's body to absorb the nutrients, NCT said.

From BBC ● Aug. 16, 2026

People with abdominal obesity alone had a 47% higher risk of death, while vitamin D deficiency by itself was associated with an increase of up to 91%.

From Science Daily ● Aug. 14, 2026

And testosterone deficiency is hard to test for, because it varies so much during the diurnal cycle.

From The Wall Street Journal ● Jul. 24, 2026

US Defence Secretary Pete Hegseth has announced that all military personnel aged 30 and over will be screened for testosterone deficiency as part of their annual health checks.

From BBC ● Jul. 17, 2026

A deficiency of these vitamins has been found to accompany mouth cancer and perhaps cancer of other sites in the digestive tract.

From "Silent Spring" by Rachel Carson

Over time, her team identified a number of serious deficiencies in the bank’s antifraud program, according to the letter.

From The Wall Street Journal ● Aug. 5, 2026

It may also contribute to iron or zinc deficiencies, both of which can interfere with the normal hair growth cycle.

From Science Daily ● Jul. 24, 2026

The report expressed concern about audit findings that identified “significant deficiencies in internal control ... that leave the district’s assets susceptible to misstatement, theft, or fraud.”

From Los Angeles Times ● Jul. 9, 2026

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

These deficiencies of astrological theory are less visible to the innumerate, who are not likely to concern themselves with mechanisms, and who are seldom interested in comparing magnitudes.

From "Innumeracy: Mathematical Illiteracy and Its Consequences" by John Allen Paulos

Related Words

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