An error or flaw in a process or product, affecting performance and potentially causing harm; a shortcoming in a legal document that may lead to its invalidity, or in a pleading that may lead to its dismissal. apparent defect. A flaw or error that should have been noticed by a reasonably observant individual. Also known as a patent defect. design defect. An error or flaw introduced, or not detected, during the design of the process or product. fatal defect. Pertaining to a contract or a plead...