defective
Americanadjective
-
Sometimes defected having a defect or flaw; faulty; imperfect.
a defective machine.
- Synonyms:
- deficient, incomplete
-
Psychology. characterized by subnormal intelligence or behavior.
-
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
adjective
-
having a defect or flaw; imperfect; faulty
-
(of a person) below the usual standard or level, esp in intelligence
-
grammar (of a word) lacking the full range of inflections characteristic of its form class, as for example must, which has no past tense
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."
Vocabulary lists containing defective
Geography and World Regions
Looking to grow your vocabulary? Check out this interactive, curated word list from our team of English language specialists at Vocabulary.com – one of over 17,000 lists we've built to help learners worldwide!
Hello, Universe
Interested in learning more words like this one? Our team at Vocabulary.com has got you covered! You can review flashcards, quiz yourself, practice spelling, and more – and it's all completely free to use!
CTE Construction ("Core Curriculum: Introductory Craft Skills,") Vocabulary from Module One
Want to remember this word for good? Start your learning journey today with our library of interactive, themed word lists built by the experts at Vocabulary.com – we'll help you make the most of your study time!
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.
“Notably, this email did not offer to refund the purchase price or advise buyers such as plaintiff that the product was defective and using it could result in catastrophic burn injuries.”
From Los Angeles Times ● Aug. 6, 2026
Misfolded and defective proteins accumulate inside cells, creating stress that can damage the pancreatic cells responsible for producing insulin.
From Science Daily ● Jul. 28, 2026
The air bags—sometimes labeled with the counterfeit logos of various carmakers—contain components called inflaters that are defective.
From The Wall Street Journal ● Jul. 9, 2026
Gruffydd Williams said: "The council should apologise profusely... for the losses they have caused by presenting defective papers to the cabinet."
From BBC ● Jun. 11, 2026
Someone sent up a flare that was defective.
From "Fallen Angels" by Walter Dean Myers
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
