defect

American  

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

noun

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

• predefect
  noun
• defectible
  adjective
• defectless
  adjective
• defectibility
  noun
• redefect
  verb (used without object)
• defector
  noun
• nondefecting
  adjective

Conjugated Forms

Present

• has defected
  perfect 3rd person singular
• have defected
  perfect
• have been defecting
  perfect progressive
• are defecting
  progressive
• is defecting
  progressive 3rd person singular
• am defecting
  progressive 1st person singular
• defecting
  participle
• has been defecting
  perfect progressive 3rd person singular
• defects
  singular 3rd person

Past

• had defected
  perfect
• was defecting
  progressive singular
• were defecting
  progressive plural
• defected
  participle
• had been defecting
  perfect progressive
• defected
  simple

Future

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

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

As for the recall, the potential defect affects some Model 3, Y, S, and X vehicles operating software version 2026.8.6.

From Barron's • May 6, 2026

Traditional product liability demands a defect in the product or its labeling.

From The Wall Street Journal • May 5, 2026

The former five-star recruit out of Sierra Canyon High is still growing into his career, especially after surgery for a congenital heart defect derailed his brief college experience.

From Los Angeles Times • Apr. 25, 2026

In such individuals, the original cause of the defect must have occurred in the generation preceding its appearance.

From "Silent Spring" by Rachel Carson

Related Words

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