"Vício oculto" is the term used by the Brazilian Consumer Code (Law No. 8,078/1990) to refer to a fault that is not promptly identifiable by the consumer, but which is detected at a later point in time. It does not keep the consumer from using the product from the beginning (sec. 26, § 3, of the Brazilian Consumer Code). As opposed to a hidden defect, a "vício oculto" is a defect that the seller or service provider does not necessarily know about in advance. The opposite of "vício oculto" is "vício aparente ou de fácil constatação" (visible or easily identifiable defect) (sec. 26 of the Brazilian Consumer Code).
There are multiple definitions - click on the translation that matches your context.
a fault that cannot be seen, that the seller or service provider knows about, and that cannot be easily discovered by close examination
If you are selling a house, and know of a hidden defect, you should seek legal advice to avoid liability down the road.