Feral
A domestic animal living wild — descended from domesticated stock, unsocialised to people, and genetically still a domestic animal rather than a wild species.
Feral is a description of how an animal lives and what it has learned, not of what species it is. A feral cat is a domestic cat that was never socialised to humans during the window when that happens easily; it may be two generations from a sofa. That is the difference between it and a wildcat, which belongs to a separate species with its own evolutionary history.
The distinction has consequences. A stray is a socialised cat that has lost its home and can usually be rehomed; a feral adult rarely can, which is why the realistic options for it are neutering and return rather than adoption.