defective

1 of 2

adjective

de·​fec·​tive di-ˈfek-tiv 

1

a

: having a defect or flaw : imperfect in form, structure, or function

replaced a defective light switch

products manufactured with defective materials

defective intestinal absorption

a defective gene

b

dated, now offensive : having a physical or mental impairment

2

grammar : lacking one or more of the usual forms of inflection (see inflection sense 2)

Must is a defective verb.

defectively adverb

defectiveness noun

defective

2 of 2

noun

1

: something that is imperfect in form, structure, or function

… if we examine 18 items off the production line, we may be interested in the number of defectives we observe …

—Lloyd Jaisingh

2

dated, now offensive : a person having a physical or mental impairment

Synonyms of defective

Adjective

• imperfect
• bad
• flawed
• faulty
• damaged
• broken

Examples of defective in a Sentence

Adjective

This computer is defective. I want my money back.

The disease is caused by a defective gene.

Recent Examples on the Web

Adjective

During the war, Joe’s factory supplied defective aircraft cylinders to the Air Force, resulting in the deaths of 21 pilots. —Demetrios Matheou, HollywoodReporter, 22 Nov. 2025

Boasberg issued a temporary restraining order and ordered that the planes be turned around, but Justice Department attorneys said his oral instructions directing the flight to be returned were defective, and the deportations proceeded as planned. —Laura Romero, ABC News, 19 Nov. 2025

Noun

After two replacement phones (one defective, the next meant for another customer and locked) and 15 different Apple customer service representatives, Holland, a publicist in Wilmington, N.C., searched online for Jobs’s email address. —Washington Post, 23 Feb. 2021

Word History

Etymology

Adjective

Middle English defectif, defectyve "lacking, faulty, of poor quality," borrowed from Anglo-French defectif, borrowed from Late Latin dēfectīvus "lacking an inflectional form, imperfect, faulty," from Latin dēfectus, past participle of dēficere "to be lacking, run short, fail" + -īvus -ive — more at deficient

Noun

derivative of defective entry 1

First Known Use

Adjective

14th century, in the meaning defined at sense 1a

Noun

1562, in the meaning defined at sense 1

Rhymes for defective

• advective
• affective
• collective
• connective
• convective
• corrective
• detective
• directive
• effective
• elective
• infective
• injective

Kids Definition

defective

adjective

de·​fec·​tive

di-ˈfek-tiv

: lacking something essential : faulty

defective brakes

defectively adverb

defectiveness noun

Medical Definition

defective

adjective

de·​fec·​tive di-ˈfek-tiv 

: falling below the norm in structure or function

a defective heart valve

defectiveness

-nəs 

noun