What does supernatural actually mean?
It means whatever human beings need it to mean. It is the answer to those questions where the answer "we don't know" is unsatisfactory or unacceptable. It is an explanation for otherwise unexplained phenomenon where an explanation must be found. It is the cause of those events for which blind random chance seems too impersonal and arbitrary. It is a provider of purpose and meaning where otherwise none might exist. It is as undetectable and mysterious as is required to protect it from investigation and possible refutation. It is need. It is comfort. It is human desire.
It is whatever human beings require it to be.