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.

Deficiency is more likely in older adults with limited sun exposure, reduced mobility, darker skin, care-home residence or diets low in vitamin D-rich foods.

From Science Daily • Jun. 6, 2026

Kenny says she has had "many conversations" with athletes suffering with Relative Energy Deficiency in Sport.

From BBC • Dec. 13, 2023

The "Deficiency Realm" human existence is a potent force.

From Scientific American • May 3, 2020

And the Immune Deficiency Foundation put out a statement in July saying doctors should find suitable alternative medicines.

From Washington Post • Nov. 1, 2019

Deficiency in either one of these desiderata is often fatal to a captain’s chances of success in his office.

From Boating by Woodgate, W. B.

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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