defect

American  

[dee-fekt, dih-fekt, dih-fekt] / ˈdi fɛkt, dɪˈfɛkt, dɪˈfɛkt /

noun

defects plural

1. a shortcoming, fault, or imperfection: a defect in a machine.

   a defect in an argument;

   a defect in a machine.

2. 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.

3. 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.

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verb (used without object)

defects, present (3rd person singular) defected, past participle, past defecting present participle

1. to desert a cause, country, etc., especially in order to adopt another (often followed by from orto ).

   He defected from the U.S.S.R. to the West.

defect British  

noun

1. a lack of something necessary for completeness or perfection; shortcoming; deficiency

2. an imperfection, failing, or blemish

3. crystallog a local deviation from regularity in the crystal lattice of a solid See also point defect dislocation

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verb

1. (intr) to desert one's country, cause, allegiance, etc, esp in order to join the opposing forces

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

• defectibility
  noun
• defector
  noun
• predefect
  noun
• defectible
  adjective
• defectless
  adjective
• nondefecting
  adjective

Inflected Forms

Nouns

• defects
  plural

Participles

• defecting
  present
• defected
  past

Conjugated Forms

Present

• defect
  simple
• defects
  simple
• have defected
  perfect
• has defected
  perfect
• am defecting
  progressive
• are defecting
  progressive
• is defecting
  progressive
• have been defecting
  perfect progressive
• has been defecting
  perfect progressive

Past

• defected
  simple
• had defected
  perfect
• was defecting
  progressive
• were defecting
  progressive
• had been defecting
  perfect progressive

Future

• will defect
  simple
• will have defected
  perfect
• will be defecting
  progressive
• will have been defecting
  perfect progressive

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.

Example Sentences

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

"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

A notice from the company described the cause of the problem as a "packaging defect".

From BBC • Jun. 6, 2026

But dealers’ share of service visits fell by 12% since 2018 as customers defect to independent repair shops, according to a Cox study that came out last year and rattled the industry.

From The Wall Street Journal • Jun. 6, 2026

I’m just like Rashid Uncle, born with a defect that makes it hard to speak, even impossible, except that you can’t see mine.

From "The Night Diary" by Veera Hiranandani

Related Words

• bug
• crack
• deficiency
• deformity
• error
• fault
• flaw
• glitch
• injury
• irregularity
• lack
• mistake
• shortage
• shortcoming
• weakness