deficiency

noun

de·​fi·​cien·​cy di-ˈfi-shən-sē 

plural deficiencies

1

: the quality or state of being defective or of lacking some necessary quality or element : the quality or state of being deficient : inadequacy

suffers from a deficiency of critical thinking

2

: an amount that is lacking or inadequate : shortage

staffing deficiencies

: such as

a

: a shortage of substances necessary to health

a vitamin C deficiency

hormone deficiencies

b

genetics : deletion sense 2b(1)

Synonyms of deficiency

• shortage
• lack

Examples of deficiency in a Sentence

The disease may be caused by nutritional deficiencies.

The book's major deficiency is its poor plot.

a deficiency of vitamin C

There are several deficiencies in his plan.

The accident was caused by deficiencies in the engine.

Recent Examples on the Web

My numbers reveal low iron, a vitamin-D deficiency, elevated cholesterol (likely genetic), and a sluggish thyroid that will require follow-up testing back home. — Abby Montanez, Robb Report, 23 Aug. 2026

The inspector noted improper date marking and food storage, as well as a lack of hot water and deficiencies in employee hygiene, according to the spokesperson. — Harriet Ramos, Fort Worth Star-Telegram, 22 Aug. 2026

If the pH gets too acidic, nitrogen uptake is greatly reduced, leading to a deficiency in the plant, even if there’s plenty of nitrogen in the potting soil. — Andy Wilcox, Better Homes & Gardens, 22 Aug. 2026

Ultimately, underperformance often signals leadership deficiencies, including poor recruitment and inadequate team management, rather than external market forces. — Bill Holmes, Forbes.com, 21 Aug. 2026

Word History

Etymology

defici(ent) entry 1 + -ency

First Known Use

1603, in the meaning defined at sense 1

Phrases Containing deficiency

• acquired immune deficiency syndrome
• deficiency disease
• mental deficiency

Rhymes for deficiency

• efficiency
• proficiency
• sufficiency
• immunodeficiency
• inefficiency
• insufficiency

Kids Definition

deficiency

noun

de·​fi·​cien·​cy di-ˈfish-ən-sē 

plural deficiencies

1

: the quality or state of being deficient

2

: the quality or state of being inadequate

especially : a shortage of substances necessary to health

Medical Definition

deficiency

noun

de·​fi·​cien·​cy di-ˈfish-ən-sē 

plural deficiencies

1

: a shortage of substances (as vitamins) necessary to health

2

: deletion

Legal Definition

deficiency

noun

de·​fi·​cien·​cy di-ˈfi-shən-sē 

plural deficiencies

: an amount that is lacking or inadequate: as

a

: the difference between the amount of tax owed and the amount of tax paid

b

: the difference between the amount owed under a security agreement and the amount the creditor is able to recover upon default of the debtor by selling the collateral