I don't think that the toy in toy court is an adjective, because it doesn't really behave like one. (It quacks like a noun.) For example, you can't really say that one court is toyer than another or that another is a very toy court. I think that what we have here is a good old nominal compound, like fire truck or baseball. But I will defend your right to call it an adjective if you want to.

Ceci n'est pas un seing.