1 of 2


: 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
chemistry : an imperfection (such as a vacancy or an unlike atom) in a crystal lattice (see lattice sense 2)


2 of 2


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

intransitive verb

: to forsake one cause, party, or nation for another often because of a change in ideology
a former KGB agent who defected to America
: to leave one situation (such as a job) often to go over to a rival
the reporter defected to another network
defector 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.
Recent Examples on the Web
Over the years, 107 people who were found not guilty by reason of mental disease or defect have been sent from Mendota to Sand Ridge. Journal Sentinel, 8 Apr. 2024 About 2 million hand steamers recalled over burn concerns 00:32 HSN — the company formerly known as Home Shopping Network — in November agreed to pay a $16 million fine after waiting years to disclose the same defect involving 5.4 million steamers recalled in May of 2021. Kate Gibson, CBS News, 4 Apr. 2024 Mild forms of these defects are present in at least 8 out of every 1,000 babies. Seth Bogner, Forbes, 27 Mar. 2024 The nuclear power plant, often called SONGS, shut down in 2013 after defects were found in its replacement steam generators. Phil Diehl, San Diego Union-Tribune, 23 Mar. 2024 So, aging is the accumulation of small defects until some critical system fails. Matt Reynolds, WIRED, 18 Mar. 2024 Filters must be free of defects including scratches, bubbles, and dents. USA TODAY, 16 Mar. 2024 Now, a coroner’s report has reportedly found that the boy died of a heart defect, with heat and physical exertion as contributing factors. Karen Garcia, Los Angeles Times, 26 Mar. 2024 According to a medical examiner’s report, the infant was full term and appeared free of natural and inflicted defects. Forum News Service, Twin Cities, 24 Mar. 2024
Helped by defecting army officers, the Fano have increasingly turned the Amhara countryside into no-go areas and are threatening major cities on the main highways leading to the capital. Alex De Waal, Foreign Affairs, 8 Apr. 2024 The companies are fighting to hold on to consumers tempted to defect from chocolate in favor of jelly beans, salty snacks or other rival treats. John Towfighi, CNN, 28 Mar. 2024 Scottie Scheffler has been voted PGA Tour player of the year over Masters champion Jon Rahm, a player vote that raises questions of whether Rahm was penalized for defecting to LIV Golf. Doug Ferguson, USA TODAY, 3 Jan. 2024 Once Eric Kendricks backed out of a verbal deal and defected to Dallas, the 49ers’ search for a starting-caliber linebacker led them elsewhere. Cam Inman, The Mercury News, 21 Mar. 2024 With the final minutes for the vote dwindling, the House watched intently on Tuesday night to see whether any more Republicans would defect on the resolution to impeach Alejandro N. Mayorkas, the homeland security secretary. Kayla Guo, New York Times, 6 Feb. 2024 Benedict Arnold, the patriot hero who defected to the British in the midst of the Revolutionary War, is remembered as the foremost fiend of his time: His name is practically synonymous with treason. Barbara Spindel, The Christian Science Monitor, 1 Mar. 2024 Enrique Garcia, who defected to the U.S. in the 1990s, also caught wind of the clandestine spy ring while running Cuban agents in Latin America. Joshua Goodman, Fortune, 15 Feb. 2024 Accounts from Myanmar army soldiers who have surrendered or defected over the past three months reveal that the military is suffering from plunging morale and overstretched logistics amid a rebel offensive that has prompted mass surrenders. Rebecca Tan, Washington Post, 14 Feb. 2024

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'defect.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History



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

First Known Use


15th century, in the meaning defined at sense 1


1596, in the meaning defined at sense 1

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

Dictionary Entries Near defect

Cite this Entry

“Defect.” Dictionary, Merriam-Webster, Accessed 17 Apr. 2024.

Kids Definition


1 of 2 noun
: a lack of something necessary for completeness or perfection


2 of 2 verb
de·​fect di-ˈfekt How to pronounce defect (audio)
: to desert a cause or party often in order to take up another
defector noun

Medical Definition


de·​fect ˈdē-ˌfekt How to pronounce defect (audio) di-ˈ How to pronounce defect (audio)
: a lack or deficiency of something necessary for adequacy in form or function
a hearing defect

Legal Definition


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

More from Merriam-Webster on defect

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