deficient

1 of 2

adjective

de·​fi·​cient di-ˈfi-shənt 

1

: lacking in some necessary quality or element

deficient in judgment

bones deficient in calcium

2

: not up to a normal standard or complement (see complement entry 1 sense 1b(1)) : defective

deficient strength

… rusted and aging pipes … abetted by deficient maintenance and sabotage.

—Adam Nossiter

deficiently adverb

deficient

2 of 2

noun

: a person or thing that is deficient

Synonyms

Adjective

• fragmental
• fragmentary
• half
• halfway
• incomplete
• partial

Examples of deficient in a Sentence

Adjective

Several bridges in the city are structurally deficient.

a diet deficient in calcium can lead to weak bones

Recent Examples on the Web

Adjective

The Strickland decision established that a defendant must show their attorney’s performance was deficient, resulting in an unfair trial, to claim their constitutional rights were violated. —The Arizona Republic, 18 Apr. 2024

The good news is that the number of structurally deficient bridges has dropped in recent years, according to the group. —Nathaniel Meyersohn, CNN, 30 Mar. 2024

Word History

Etymology

Adjective

borrowed from Latin dēficient-, dēficiens, present participle of dēficere "to leave without enough, let down, be lacking, run short, fail," from dē- de- + facere "to make, bring about, perform, do" — more at fact

Noun

derivative of deficient entry 1

First Known Use

Adjective

1581, in the meaning defined at sense 1

Noun

1906, in the meaning defined above

Kids Definition

deficient

adjective

de·​fi·​cient

di-ˈfish-ənt

: lacking something necessary for completeness : not up to a given or normal standard

a diet deficient in proteins

deficient in their knowledge of history

deficiently adverb

Medical Definition

deficient

adjective

de·​fi·​cient di-ˈfish-ənt 

1

: lacking in some necessary quality or element

a deficient diet

2

: not up to a normal standard or complement

deficient strength

3

: having, relating to, or characterized by a genetic deletion