Functional defects refer to issues in a product or system that prevent it from performing its intended tasks or functions. These defects can occur in various contexts, such as software applications, electronic devices, or machinery. They often lead to errors, malfunctions, or a complete failure to operate as expected. Identifying and addressing functional defects is crucial for ensuring quality and reliability. In software development, for example, bugs are common functional defects that can disrupt user experience. Regular testing and quality assurance processes help detect these issues early, allowing for timely fixes and improvements before the product reaches the market.