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.

---

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

---

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

Symptoms can include periods lasting more than seven days, the need to change sanitary protection every one to two hours, passing large blood clots and signs of iron deficiency such as fatigue and dizziness.

From BBC ● Aug. 26, 2026

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 who had both abdominal obesity and vitamin D deficiency faced a 123% higher risk of death compared with those who had neither condition.

From Science Daily ● Aug. 14, 2026

Alexandre says abdominal obesity and vitamin D deficiency may reinforce one another in a harmful cycle.

From Science Daily ● Aug. 14, 2026

As with so many other things, time is the key factor—speed in discovering the deficiency, and speed in administering hormonal substitutes.

From "Flowers for Algernon" by Daniel Keyes

Because GLP-1 drugs reduce appetite and food intake, they may also contribute to nutritional deficiencies and loss of muscle, potentially increasing the risk of frailty and other long-term health issues.

From Science Daily ● Aug. 23, 2026

“We believe … that the Contractor could have been able to exploit the deficiencies in the Contract to their maximum benefit,” the report reads.

From Los Angeles Times ● Aug. 14, 2026

London-listed shares in fintech company Wise Group fell after U.S. regulators denied its application for a national trust bank license, citing deficiencies in its program to combat money laundering and terrorism financing.

From The Wall Street Journal ● Jul. 24, 2026

It cited long-standing deficiencies in anti-money laundering and countering the financing of terrorism at Wise U.S.

From The Wall Street Journal ● Jul. 24, 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