defective

Defective is an adjective used to describe something that does not work as intended or contains flaws. It can apply to manufactured goods, components, systems, or processes, and by extension to biological or mechanical abnormalities. The term is commonly used in contexts such as engineering, quality control, and product safety, where it denotes failure to meet required specifications or performance standards. The opposite term is defect-free or non-defective.

Etymology and usage. Defective derives from Late Latin defectivus, from defect- “a failure,” from the verb deficere “to fail.” In English, it has been used since the 15th century to describe faults or imperfections in objects, materials, or designs. In technical writing, it often appears alongside terms like defect, defect rate, and quality assurance.

Legal and safety context. In consumer protection and product liability, a product may be labeled defective if its design, manufacture, or labeling renders it unreasonably dangerous or unfit for its intended use. Investigations, recalls, repairs, replacements, or refunds may follow. Quality-management practices track defective items to reduce defect rates and improve reliability.

People and sensitivity. When applied to humans, defective is generally considered inappropriate or stigmatizing. It is more appropriate to describe specific conditions, abilities, or impairments, or to use person-centered language that respects autonomy and dignity.

Related terms. Defect refers to a shortcoming or flaw itself; defective describes the state of having defects. Related concepts include defect rate, defect density, defect tracking, and defect prevention within quality systems.