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

Most of us suffer from magnesium deficiency due to high levels of stress and poor digestion, which adds up to poor absorption of nutrients. —Marie Bladt, Vogue, 15 Nov. 2025

According to multiple scouts, the Clippers' profound lack of speed and fluidity is their biggest problem, and their other issues seem to flow from that deficiency. —Robert Marvi, MSNBC Newsweek, 15 Nov. 2025

Why hide deficiencies instead of overcoming them? —Big Think, 14 Nov. 2025

Children and babies experiencing food insecurity are more likely to have nutrient deficiencies, including insufficient iron. —Jenalee Doom, The Conversation, 14 Nov. 2025

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