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)

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

Related Words

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

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

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” ( deficient ) + -tus suffix of verb action

Example Sentences

By 2023, he had a heart attack and was diagnosed with a congenital heart defect and cauda equina syndrome, the latter led to several spinal surgeries.

From Salon • Mar. 21, 2026

There’s an understanding among the leagues that given Fanatics ships around 100-million items per year, an error or defect rate of just 1% would result in hundreds of thousands of upset customers.

From Los Angeles Times • Feb. 22, 2026

Although California could in theory address this defect, the ruling illustrates the constitutional challenges that states face when regulating a federal agency, and shows the need for a uniform, nationwide rule from Congress.

From Slate • Feb. 19, 2026

But the changes Karp enacted have rippled across the industry as firms have grown and teams of lawyers now routinely defect to competing firms like baseball free agents.

From The Wall Street Journal • Feb. 6, 2026

Levy Pants was like a congenital defect, an inherited curse.

From "A Confederacy of Dunces" by John Kennedy Toole

Related Words

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