Definitions

deficiency

[dih-fish-uhn-see] / dɪˈfɪʃ ən si /

NOUN

imperfection, inadequacy

Synonyms

STRONGEST

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

STRONG

absence bug defalcation default deficit demerit dereliction loss need neglect paucity privation scantiness sin want

WEAK

inability to hack it insufficience

Antonyms

STRONGEST

abundance advantage enough excess perfection plenty strength strong point success sufficiency surplus

STRONG

accomplishment achievement

WEAK

adequacy faultlessness satisfaction superfluity

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

But B12 deficiency should be considered before folate is prescribed on its own, because folate can improve some blood signs of B12 deficiency while nerve damage continues.

From Science Daily • Jun. 6, 2026

This is why B12 deficiency is taken seriously.

From Science Daily • May 27, 2026

They do, however, suggest that the current definition of B12 deficiency may be too blunt for brain health.

From Science Daily • May 22, 2026

B12 is clearly essential for the nervous system, and deficiency should not be ignored.

From Science Daily • May 22, 2026

Lucinda’s death leaves us with a serious deficiency in the freak lineup.

From "Water for Elephants" by Sara Gruen

Vocabulary lists containing deficiency

Freak the Mighty

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Flowers for Algernon

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Paltry Parlance: Synonyms for "Few"

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