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defective

American  
[dih-fek-tiv] / dɪˈfɛk tɪv /

adjective

  1. Sometimes defected having a defect or flaw; faulty; imperfect.

    a defective machine.

    Synonyms:
    deficient, incomplete
    Antonyms:
    complete, perfect
  2. Psychology. characterized by subnormal intelligence or behavior.

  3. Grammar. (of an inflected word or its inflection) lacking one or more of the inflected forms proper to most words of the same class in the language, as English must, which occurs only in the present tense.


noun

  1. a defective person or thing.

defective British  
/ dɪˈfɛktɪv /

adjective

  1. having a defect or flaw; imperfect; faulty

  2. (of a person) below the usual standard or level, esp in intelligence

  3. grammar (of a word) lacking the full range of inflections characteristic of its form class, as for example must, which has no past tense

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Other Word Forms

Etymology

Origin of defective

First recorded in 1375–1425; from Late Latin dēfectīvus, equivalent to dēfectus ( see defect) + -īvus -ive; replacing Middle English defectif, from Middle French, from Late Latin, as above

Explanation

Something that's defective doesn't work quite right, because it's damaged in some way. Your defective car probably won't make it all the way to California from New York. Defective things are broken or flawed. A defective blender won't mix your morning smoothie the way you want it to, and a defective law doesn't serve the people it's meant to protect. A very old-fashioned meaning of defective, which is considered quite offensive today, is "mentally ill" or "mentally handicapped." The Late Latin root is defectivus, "to fail, revolt, or desert."

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Vocabulary lists containing defective

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

The sixth, defective core was disabled, leaving a still good chip and allowing them to be used in the MacBook Neo.

From The Wall Street Journal • May 18, 2026

Judges at a district court in Hanover ruled in his favour, and said the family of four were entitled to a larger refund on their package holiday as it had been "defective".

From BBC • May 6, 2026

Spirit had another recent problem that wasn’t its fault: the defective engines on the Airbus planes.

From Slate • May 5, 2026

In her vision, Warhol’s Factory is a literal assembly line, where actors and artists come to be molded and assembled into products, only to be cast out when they’re deemed defective.

From Salon • Apr. 29, 2026

I ask him, genuinely wondering what would possess someone with defective lungs to take a trip onto the roof in the dead of winter.

From "Five Feet Apart" by Rachael Lippincott

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