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
Hello, Universe
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Geography and World Regions
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CTE Construction ("Core Curriculum: Introductory Craft Skills,") Vocabulary from Module One
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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 scientists also explored whether their approach could help treat conditions involving defective immune defenses.
From Science Daily ● Oct. 16, 2026
But for all his talents, he will be remembered as a man affected by a defective moral compass, whose public humiliation was entirely self-inflicted.
From BBC ● Oct. 5, 2026
“In addition, the Korean entities’ U.S.-specific design supported the conclusion that they purposefully directed the defective vehicles to California.”
From Los Angeles Times ● Sep. 15, 2026
The defective hemoglobin sticks to itself, causing normally flexible cells to stiffen into sickle shapes—a process sometimes called sickling—that block blood flow, damage organs and trigger excruciating pain.
From The Wall Street Journal ● Sep. 9, 2026
Each screen was showing the same video of a defective robot’s broken body.
From "The Wild Robot Escapes" by Peter Brown
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Get a wordDefinitions 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.
