defect
Americannoun
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a shortcoming, fault, or imperfection: a defect in a machine.
a defect in an argument;
a defect in a machine.
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lack or want, especially of something essential to perfection or completeness; deficiency: a defect of action.
a defect of common sense
a defect of action.
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Also called lattice defect. Also called crystal defect,. Crystallography. a discontinuity in the lattice of a crystal caused by missing or extra atoms or ions, or by dislocations.
verb (used without object)
noun
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a lack of something necessary for completeness or perfection; shortcoming; deficiency
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an imperfection, failing, or blemish
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crystallog a local deviation from regularity in the crystal lattice of a solid See also point defect dislocation
verb
Synonym Usage
Defect, blemish, flaw refer to faults that detract from perfection. Defect is the general word for any kind of shortcoming or imperfection, whether literal or figurative: a defect in eyesight, in a plan. A blemish is usually a defect on a surface, which mars the appearance: a blemish on her cheek. Flaw is applied to a defect in quality, caused by imperfect structure (as in a diamond) or brought about during manufacture (as in texture of cloth, in clearness of glass, etc.).
Other Word Forms
Derived Forms
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defectibilitynoun
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defectornoun
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predefectnoun
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defectibleadjective
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defectlessadjective
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nondefectingadjective
Inflected Forms
Nouns
Participles
Conjugated Forms
Present
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defectsimple
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defectssimple
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have defectedperfect
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has defectedperfect
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am defectingprogressive
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are defectingprogressive
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is defectingprogressive
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have been defectingperfect progressive
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has been defectingperfect progressive
Past
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defectedsimple
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had defectedperfect
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was defectingprogressive
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were defectingprogressive
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had been defectingperfect progressive
Future
Etymology
Origin of defect
First recorded in 1375–1425; late Middle English, from Latin dēfectus “failure, weakness,” equivalent to dēfec-, variant stem of dēficere “to run short, fail, weaken” ( see deficient) + -tus suffix of verb action
Explanation
A flaw in something is a defect. At certain stores you can buy clothes with slight defects. You have to be careful because the defect can be minor, like a missing button, or major, like sleeves of uneven lengths. In a person, a defect is an imperfection, which can manifest itself mentally or physically. If you are diagnosed with a heart defect, you will have to seek the advice of specialists. A hearing defect might leave your dad deaf in one ear. If you are becoming forgetful, you can joke that you are developing a mental defect, but if it continues, you'll probably want to have your head examined.
Vocabulary lists containing defect
Tuesdays with Morrie
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The Glass Menagerie
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Thomas Jefferson's First Inaugural Address (1801)
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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.
"Our results suggest that altered metabolism is a significant contributor to Alzheimer's progression and, in addition, addressing the metabolic defect could be an important complement to approaches focused on Alzheimer's plaques and tangles," Sun said.
From Science Daily • Jun. 10, 2026
The defect was traced back to supplier production quality and Boeing’s inability to catch it.
From Barron's • May 28, 2026
Emily Bowen and Mathew Mariani felt their worries were "palmed off" but it turned out baby Esme had a serious heart defect that needed surgery.
From BBC • May 23, 2026
In early May, about 3,800 of Waymos autonomous taxis were recalled after a software defect caused some vehicles to drive into flooded roadways.
From Los Angeles Times • May 22, 2026
He was told he had a heart defect, and it was serious enough for the Army Board to turn him down.
From "The Woman All Spies Fear" by Amy Butler Greenfield
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.
