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

“Typically by around 10 to 12 years of age, people that are likely to have a deficiency in the enzyme have developed it to the capacity,” says Sibley.

From The Wall Street Journal ● Oct. 12, 2026

The founders wrote the Constitution in part to fix that deficiency.

From The Wall Street Journal ● Oct. 2, 2026

Saul and Drew have both since recovered but take daily antibiotics after tests revealed they both had properdin deficiency - a rare immunodeficiency which means they are more susceptible to infections such as meningitis.

From BBC ● Sep. 29, 2026

“Conditions such as depression, lack of sleep, a low-functioning thyroid, and vitamin B12 deficiency can lead to memory loss that mimic the early stages of dementia,” Tan writes.

From Los Angeles Times ● Sep. 23, 2026

Her own father’s perfect exemption from any thought of the kind, the entire deficiency in him of all such sort of penetration or suspicion, was a most comfortable circumstance.

From "Emma" by Jane Austen

Studies on Baiga households have found widespread nutritional deficiencies, compounded by poor uptake, external of public services.

From BBC ● Sep. 30, 2026

So, arbitrarily boosting testosterone is not good for young men without deficiencies.

From Slate ● Sep. 13, 2026

"The fundamental root cause... resulting in a catastrophe, was the deficiencies and failures on the bridge of the M/T ALSU," it said.

From Barron's ● Sep. 3, 2026

One planned approach is stable isotope analysis, which could provide additional information about diet and help researchers better understand evidence of nutritional deficiencies.

From Science Daily ● Aug. 30, 2026

Hoover, who believed that his men should conquer their deficiencies the way he had conquered his childhood stutter, purged anyone who failed to meet his exacting standards.

From "Killers of the Flower Moon" by David Grann

Related Words

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