Faulty

Faulty is an adjective used to describe something that contains a fault or defect, or that fails to perform as intended. It can apply to physical objects such as devices or structures, to processes or systems, and to information or reasoning.

In everyday usage, a faulty item does not work correctly or safely, for example a faulty toaster or faulty brakes. In science and engineering, professionals describe components as faulty when they do not meet specifications, produce incorrect results, or are prone to malfunction. The term also appears in descriptions of memory, perception, or data that are unreliable or erroneous, as in faulty memory or faulty data.

In logic and rhetoric, a faulty argument contains errors in reasoning, such as faulty generalization, faulty causation, or other fallacies, which undermine the argument’s validity. The phrase faulty logic is commonly used to indicate reasoning that is structurally unsound or misleading.

Quality control, safety regulation, and consumer protection use the term to identify defects in products or processes. Identifying faulty components can lead to inspections, recalls, repairs, or warranty claims, and it is often contrasted with terms like defective, flawed, or malfunctioning.

Etymology and usage: faulty derives from the noun fault with the addition of the suffix -y, and has been part of English since the Late Middle Ages. Related terms include defect, flaw, malfunction, and reliability. See also fault (noun) for the underlying concept of a shortcoming or failure.