deficient

American  

[dih-fish-uhnt] / dɪˈfɪʃ ənt /

adjective

1. lacking some element or characteristic; defective.

   deficient in taste.

2. insufficient; inadequate.

   deficient knowledge.

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noun

1. a person who is deficient, especially one who is mentally defective.

deficient British  

/ dɪˈfɪʃənt /

adjective

1. lacking some essential; incomplete; defective

2. inadequate in quantity or supply; insufficient

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Other Word Forms

• deficiently adverb
• nondeficient adjective
• nondeficiently adverb
• predeficient adjective
• predeficiently adverb
• undeficient adjective
• undeficiently adverb

Etymology

Origin of deficient

First recorded in 1575–85; from Latin dēficient-, stem of dēficiēns “failing,” present participle of dēficere “to fail, run short, lack, weaken,” from dē- de- + ficere, combining form of facere “to do, make” ( do ¹ )

Example Sentences

The agreement Barnett reached with LaBeouf “contained a deficient and unlawful NDA that is unenforceable,” under California’s Stand Together Against Non-Disclosure Act, according to the complaint.

From Los Angeles Times • Mar. 26, 2026

Deere leverages AI to help farmers cut costs—by reducing labor required to operate equipment, minimizing wasted crop chemicals, and applying fertilizer more precisely where soil nutrients are deficient.

From Barron's • Feb. 2, 2026

Meanwhile, older people think I’m somehow financially deficient because I rent.

From The Wall Street Journal • Jan. 20, 2026

In a randomized clinical trial, magnesium increased vitamin D in people who were deficient, while reducing levels in those who already had high amounts.

From Science Daily • Dec. 30, 2025

On bad days it was a reminder of all the ways I am deficient.

From "Dry" by Neal Shusterman and Jarrod Shusterman

Related Words

• defective
• faulty
• flawed
• impaired
• incomplete
• inferior
• insufficient
• lacking
• scarce
• skimpy
• unsatisfactory
• weak