What does defective mean?
"Defective" is an adjective describing something marred by a fault or imperfection that keeps it from working properly or meeting the required standard. A defective brake pad, for instance, fails to perform its intended function safely; a defective title makes a property claim legally unsound. The word is especially at home in formal registers — consumer law, engineering, medicine, and quality control all rely on it heavily — which gives it a precise, technical flavor compared with looser synonyms like "bad" or "broken." Beyond physical objects, it extends to documents and arguments judged invalid, and in grammar it labels words, typically verbs, that lack certain expected forms. Derived from the Latin "deficere," meaning to fail or run short, "defective" shares its ancestry with "deficit" and "deficiency." Its usefulness lies in naming not just any imperfection, but a specific failing with real consequences — a word that turns vague dissatisfaction into an actionable diagnosis.
Having a fault or flaw that impairs function, quality, or validity; imperfect.
"The court voided the agreement because the signature page was defective."
Common in legal, technical, and consumer contexts; can sound clinical when applied to people.
A defective person or thing; in grammar, a word lacking some of the usual inflected forms of its class.
"Linguists classify "can" as a defective because it lacks an infinitive form."
As a noun referring to people, this usage is now considered offensive and dated; it survives mainly in linguistic terminology.
Used only in specialized contexts such as linguistics, where "defectives" refers collectively to defective verbs or other under-inflected words.
"Modal verbs are among the best-known defectives in English grammar."
In law and linguistics, "defective" gets surprisingly technical — even perfectly common verbs like "can" are officially called defective because they refuse to be conjugated like everyone else.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of defective
"Defective" comes from the Latin verb "deficere," meaning "to fail, lack, or desert," formed from "de-" (away) plus "facere" (to do or make). English adopted it in the late Middle English period, around the 15th century, initially in the sense of lacking something needed. The same root produced "deficit" directly from Latin, while "defect" and "deficiency" entered English through related Latin noun forms, making them true etymological siblings rather than derivatives.
Related word forms
How defective is actually used
"Defective" carries a neutral-to-negative connotation and appears frequently in legal, manufacturing, medical, and consumer-protection contexts. When applied to people it can sound clinical or offensive, so careful writers usually prefer more specific terms. It is standard in both British and American English, though "faulty" is often the more colloquial choice in everyday speech.
Easily confused with defective
"Defective" means broken or flawed so something does not work properly, while "deficient" means lacking an adequate amount of something needed.