There is alway the word:
Friend that supersedes the word supernatural.
Language is about history.
I don't see the problem here~ even using that definition, it doesn't change anything.
"supernatural can be real, god can be real (per definition)"
"ok, well, give me another example of something that is real and supernatural."
"ok, then god is on the same level as ghosts"
Just saying, I don't think that the definition, regardless of what it implies, makes any difference in an argument. Doesn't lend any credence to a Bs argument.
supernatural: attributed to some force beyond scientific understanding or the laws of nature : a supernatural being.
Fiction: literature in the form of prose, esp. short stories and novels, that describes imaginary events and people.
They could be but don't have to be the same thing at all.