deficient
Americanadjective
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lacking some element or characteristic; defective.
deficient in taste.
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insufficient; inadequate.
deficient knowledge.
noun
adjective
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lacking some essential; incomplete; defective
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inadequate in quantity or supply; insufficient
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
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
Iran, which is an IMO member but does not sit on its council, hit out at the declaration, branding it "one-sided, unfair, inaccurate and legally deficient".
From Barron's • Mar. 19, 2026
“Our animals and us are actually super deficient in light, especially the most healing wavelengths that we have,” says Jackie Jolie, CEO of AnimaSol.
From The Wall Street Journal • Jan. 28, 2026
Lacking one of their top players with guard Skyy Clark sidelined by a hamstring injury, the Bruins also were deficient in many other areas.
From Los Angeles Times • Jan. 6, 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
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
