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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redefectverb (used without object)
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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.
See Examples For:
He later was diagnosed with a congenital heart defect but eventually was able to resume his basketball career.
From Los Angeles Times ● Jul. 17, 2026
Shortly after, DTN said it believed the inflaters were counterfeits manufactured by another company, and that “the related accidents were not necessarily caused by a defect in the inflater.”
From The Wall Street Journal ● Jul. 9, 2026
Jolie’s mother had breast cancer and died of ovarian cancer, and her aunt, who had the same BRCA1 gene defect as Jolie, died of breast cancer three months after Jolie’s operation.
From Salon ● Jun. 29, 2026
The approach relies on a diamond containing a microscopic magnetic defect formed by a nitrogen atom and a missing neighboring carbon atom.
From Science Daily ● Jun. 23, 2026
From the moment she learned that she was pregnant, my grandmother was again tormented by fears that the baby would suffer a hideous birth defect.
From "Middlesex: A Novel" by Jeffrey Eugenides
"It is the first time we know the exact number of Laron syndrome patients and the many variants of the growth hormone receptor defects," he tells BBC Mundo.
From BBC ● Jul. 17, 2026
In the worm's jaws, sharper changes in strain across tiny regions appear to increase the interlocking of defects within the atomic structure, producing the characteristic size effect.
From Science Daily ● Jul. 16, 2026
"Other schedule risks remain, including the detailed designs for the aircraft interiors, fabrication of the wire bundles, and rework to correct defects in structural modifications," the report said.
From Barron's ● Jul. 2, 2026
Factors include “older buildings that do not meet modern seismic standards, as well as hidden defects or structural vulnerabilities,” De Santis said.
From Los Angeles Times ● Jun. 27, 2026
“Everyone who defects has adjustment problems,” Ko Gyoung-bin, the director-general of Hanawon, told me when I visited the place.
From "Escape from Camp 14: One Man's Remarkable Odyssey from North Korea to Freedom in the West" by Blaine Harden
But last week, the replies were inundated with complaints that Letterboxd had defected to the corporate dark side, along with fearful pleas for the platform’s owners to reconsider.
From Salon ● Jul. 15, 2026
It was in 1990, while touring Europe with his hero Gillespie, that Sandoval finally defected from Cuba with his wife and son — and found the refuge he’d been seeking in the U.S.
From Los Angeles Times ● Jun. 12, 2026
The U.S. auto industry faces sobering new math: Some one million prospective buyers have defected from the new-car market since the start of the decade—and they aren’t expected back soon.
From The Wall Street Journal ● May 28, 2026
But he has now defected to Reform UK.
From BBC ● May 8, 2026
My mother embraced Edward after he defected from Dauntless.
From "Allegiant" by Veronica Roth
Jaber Rajabi, who served in the Revolutionary Guard and studied with Khamenei in a religious seminary in Qom before defecting in 2016, warned Iran’s Arab neighbors about him before his elevation.
From The Wall Street Journal ● Apr. 15, 2026
The defecting lawmakers are making it heard that their decision wasn’t taken lightly.
From Salon ● Jan. 9, 2026
It’s good for firms to have a healthy fear of their users defecting somewhere else.
From Slate ● Oct. 13, 2025
While Badenoch was conducting a string of media interviews, Reform UK announced that 20 Conservative councillors were defecting.
From BBC ● Oct. 7, 2025
“We risked our lives by defecting from our faction,” says Cara, “and we will risk them again to save our faction from itself.”
From "Insurgent" by Veronica Roth
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.