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.

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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

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Other Word Forms

• defectively adverb
• defectiveness noun
• nondefective adjective
• nondefectively adverb
• nondefectiveness noun
• predefective adjective
• undefective adjective
• undefectively adverb
• undefectiveness noun

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."

Example Sentences

Reading a summary of their ruling, judges said the jurors at trial had "not been properly directed" and the directions given to them on how to reach a verdict were "defective".

From BBC • Apr. 16, 2026

It does not, on its face, shield these corporations from suit as the creators of a defective product that negligently serves users this speech in harmful ways.

From Slate • Mar. 30, 2026

“Despite having been on notice of the many serious injuries and/or fatalities caused by the defective design of their vehicles, including the Cybertruck, Tesla continued to manufacture and sell such dangerous vehicles.”

From Los Angeles Times • Mar. 19, 2026

This tension, he said, was compounded by subsequent U.S. intelligence reports alleging that widespread corruption had rendered some of these missiles nonfunctional—including claims of defective silo lids.

From The Wall Street Journal • Feb. 20, 2026

Her husband dead, three children sold, the fourth defective, and her having to thank God for the defect.

From "Kindred" by Octavia Butler

Related Words

• abnormal
• damaged
• deficient
• faulty
• flawed
• inadequate
• insufficient
• unhealthy
• unsound