Imperfection, flaw, or deficiency.
That which is subject to a defect is missing a requisite element and, therefore, is not legally binding. Defective SERVICE OF PROCESS, for example, is service that does not comply with a procedural or jurisdictional requirement. A defective will is one that has not been properly drawn up, has been obtained by unlawful means, or does not comply with a particular law. In some cases, however, defects can be cured; for example, defective service of process can be cured by the service of an amended complaint.
In PRODUCT LIABILITY, a defective product is one that cannot be used for the purposes intended or is made dangerous as a result of a flaw or imperfection. Such a defect might exist in the entire design of a product or in the production of a particular individual product. A latent defect is one that is not readily observable by the buyer of an item, whereas a patent defect is obvious or immediately apparent upon observation.
A fatal defect is one that, due to its serious nature, serves to nullify a contract.
Law Library - American Law and Legal InformationFree Legal Encyclopedia: Deed of covenant to Direct Tax