An imperfection in a product that has a manufacturing defect or design defect, or is faulty because of inadequate instructions or warnings. When something goes wrong during the manufacturing process, it can lead to a defective product that fails to work as intended.A product is defective when it poses an unreasonable risk to those who use the product as it is intended to be used. Product liability is the area of law in which manufacturers, distributors, suppliers and retailers are held responsible for any injuries products cause. You only have to prove that a product was defective when it left their control, and that defect resulted in a personal injury or wrongful death. A design defect is a flaw in the original design of the product that makes it unreasonably dangerous. What Is a Product Defect? When a product is defective, it means that the product has some kind of flaw or problem that makes it unreasonably dangerous to use. DeLonghi and Home Depot state that the above arguments indicate that they have demonstrated prima facie entitlement to judgment as a matter of law. Results from a defect in the product of which the consumer is not aware.