de·​fect | \ ˈdē-ˌfekt How to pronounce defect (audio) , di-ˈfekt How to pronounce defect (audio) \

Definition of defect

 (Entry 1 of 2)

1 : an imperfection or abnormality that impairs quality, function, or utility : shortcoming, flaw carefully inspect a tire for defects examined the porcelain for defects a moral defect in his nature neural tube defects defects of metabolism
2 chemistry : an imperfection (such as a vacancy or an unlike atom) in a crystal lattice (see lattice sense 2)


de·​fect | \ di-ˈfekt How to pronounce defect (audio) \
defected; defecting; defects

Definition of defect (Entry 2 of 2)

intransitive verb

1 : to forsake one cause, party, or nation for another often because of a change in ideology a former KGB agent who defected to America
2 : to leave one situation (such as a job) often to go over to a rival the reporter defected to another network

Other Words from defect


defector \ di-​ˈfek-​tər How to pronounce defect (audio) \ noun

Examples of defect in a Sentence

Noun They examine their products for defects. She was born with a heart defect. Vanity and pride were his two worst character defects. Verb The Russian scholar defected in 1979. She defected from the conservative party. He defected to the West before the war began. The reporter defected to another TV network. See More
Recent Examples on the Web: Noun Geyser has remained at the Winnebago Mental Health Institute since she was found not guilty by reason of mental disease or defect in 2018. Jim Riccioli, Journal Sentinel, 11 Aug. 2022 Ford has acknowledged that fires are caused by a manufacturing defect in a battery junction box, and has advised customers to park away from structures while waiting for the part, the law firm noted. Phoebe Wall Howard, Detroit Free Press, 12 July 2022 Their child would be born with a heart defect and other problems; terminating the pregnancy would be best, the doctors advised. Jennifer Hassan, Washington Post, 28 Aug. 2022 The girl was born with a heart defect but doctors saved her. Hanna Arhirova, ajc, 15 July 2022 Jason was born with a heart defect and received a transplant at age 6. Clifford Ward, Chicago Tribune, 3 May 2022 In one of the pregnancies in the study, the fetus was diagnosed with a heart defect in utero. New York Times, 20 Apr. 2022 The hospital has said she was born with a rare heart defect and suffered from chronic lung disease and severe chronic high blood pressure. Jamie Stengle, Chron, 13 Apr. 2022 This can happen for a variety of reasons, such as being born with a heart defect or getting a severe infection like the flu, which can lead to heart inflammation. Ashley Abramson, SELF, 13 Apr. 2022 Recent Examples on the Web: Verb Republicans claimed betrayal and threatened to defect from the House vote. Globe Staff,, 8 Aug. 2022 As Democrats wield a thin 220-210 majority – only a handful of pro-SALT deduction Democrats needed to defect for the bill to fail. Kenneth Tran, USA TODAY, 8 Aug. 2022 The skating world is watching for clues that Diana Davis, Tutberidze’s ice dancer daughter, might effectively defect as a competitor to the U.S., where Davis is already a citizen. Louise Radnofsky, WSJ, 7 Aug. 2022 Charles Barkley won’t defect to the LIV Tour, which is a shame, because the move would have given him a chance to win his first tournament. Nick Canepacolumnist, San Diego Union-Tribune, 30 July 2022 Quartz spoke with Matt Brown, the publisher of Extra Points, a newsletter that covers the business of college sports, about how the pursuit of money and collective power led USC and UCLA to defect. Scott Nover, Quartz, 20 July 2022 Recent weeks have seen other coalition backbenchers threaten to defect or openly vote against the government. Neri Zilber, The Christian Science Monitor, 14 June 2022 For the pro-am, Trump was grouped with two of the best players to defect to the rival LIV Golf circuit from the PGA Tour: Dustin Johnson and Bryson DeChambeau, who have won three major championships between them. New York Times, 28 July 2022 The earnings come as consumer-goods companies walk a tightrope in deciding how much to lift the prices of their products to offset rising costs without propelling shoppers to defect to cheaper store brands amid rising inflation. Saabira Chaudhuri, WSJ, 26 July 2022 See More

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'defect.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

First Known Use of defect


15th century, in the meaning defined at sense 1


1596, in the meaning defined at sense 1

History and Etymology for defect


Middle English, borrowed from Latin dēfectus "failure, absence, lack, weakness," from dēficere "to be lacking, run short, weaken, fail" + -tus, suffix of action nouns — more at deficient


borrowed from Latin dēfectus, past participle of dēficere "to be lacking, fail, become disaffected, go over (to the side of an opponent)" — more at deficient

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The first known use of defect was in the 15th century

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Last Updated

17 Sep 2022

Cite this Entry

“Defect.” Dictionary, Merriam-Webster, Accessed 26 Sep. 2022.

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More Definitions for defect


de·​fect | \ ˈdē-ˌfekt How to pronounce defect (audio) , di-ˈfekt \

Kids Definition of defect

1 : something that makes a thing imperfect : flaw A slight defect lowered the diamond's value.
2 : a lack of something needed for perfection Doctors can correct the hearing defect.


de·​fect | \ ˈdē-ˌfekt How to pronounce defect (audio) , di-ˈ How to pronounce defect (audio) \

Medical Definition of defect

: a lack or deficiency of something necessary for adequacy in form or function a hearing defect


de·​fect | \ ˈdē-ˌfekt, di-ˈfekt How to pronounce defect (audio) \

Legal Definition of defect

: something or a lack of something that results in incompleteness, inadequacy, or imperfection: as
a : a flaw in something (as a product) especially that creates an unreasonable risk of harm in its normal use — see also latent defect
b : an error or omission in a court document (as an indictment or pleading)
c : some imperfection in the chain of title to property that makes the title unmarketable

Other Words from defect

defective \ di-​ˈfek-​tiv How to pronounce defect (audio) \ adjective
defectively adverb
defectiveness noun

More from Merriam-Webster on defect

Nglish: Translation of defect for Spanish Speakers

Britannica English: Translation of defect for Arabic Speakers Encyclopedia article about defect


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