If something is disputable, it is not safely settled. A careful person could still argue that it is not true, or not right. The facts may be thin, the rule may be unclear, or honest people may read the same thing two ways. It is a rather formal adjective. You will see it in essays and news more than in chat. Though actually, calling something disputable is often a polite way of saying “I do not fully accept this” without calling anyone a liar. Note that disputable does not mean “we are already fighting”; it means the point is still open to argument.