The definition of feral is probably, a cat with domestic ancestry, living wild typically after a couple om more of generations as homeless, without natural contacts with humans.... It lives and behaves like a wild.
The true european wild cats is another subspecies of small cat than our domestics, although they may look alike. The wild cat is impossible or at least - very difficult to domesticize. - Our feral cat isnt very difficult to make domestic or sometimes even family pet. There are two wide open windows: taken in as a kitten (2-7 weeks), or if taken in and nursed when sick or wounded. But almost all other variations are possible - although it usually takes time and patience...Sometimes loong time.
Other wild cat subspecies may be easier to domesticize then the european wild cat - feks the african wildcat Lybica(?) is almost as easy to domesticize as our domestic cat. Thus, the ancestor of our pet cats is the Lybica, not the european wild cat.
Even the big Fisher cat of east asia ist easier to domesticize than the european wild cat.
*question: Do anybody knows if there was a successfull try to domesticize a european wild cat? Say taken in as young?*
The interesting is the "semiferal" cat. This is all the homeless inbetweens we dont really know much about.
Some MAY be a feral cat who isnt much afraid of people. Cats are partly individual, see. So this happens, especielly with some kittens, and also some toms.
Other semiferal may be a stray or dumped pet cat, who survived and now lives more or less successfully as homeless shy semiferal.
Question is, if we shall call these barn cats mentioned as ferals or semiferals... They usually do have some connection with the peasant family where they do belong. But this is perhaps another story.