If I believe that the Spaghetti Monster lives under my bed, what word would you use to describe this? It can not be proven that the Spaghetti Monster does not live under my bed because you have not looked there but I also have not proven it to be true myself. It's not a religious belief because religious beliefs are by definition "the belief in and worship of a superhuman controlling power, especially a personal God or gods" and this is not a belief in a higher power, just a scary Spaghetti Monster. And it's also not a scientific belief because it has not been scientifically proven. Furthermore, it is not a false belief because one has not proved it to be false.
Hope this makes sense.