No what's not?
Supernatural
1 : of or relating to an order of existence beyond the visible observable universe; especially : of or relating to God or a god, demigod, spirit, or devil
2 a : departing from what is usual or normal especially so as to appear to transcend the laws of nature b : attributed to an invisible agent (as a ghost or spirit)
su·per·nat·u·ral (spr-nchr-l)
adj.
1. Of or relating to existence outside the natural world.
2. Attributed to a power that seems to violate or go beyond natural forces.
3. Of or relating to a deity.
4. Of or relating to the immediate exercise of divine power; miraculous.
5. Of or relating to the miraculous.
SOURCE:
supernatural - definition of supernatural by the Free Online Dictionary, Thesaurus and Encyclopedia.
"The term supernatural or supranatural (Latin: super, supra "above" + natura "nature") pertains to being above or beyond what one holds to be natural"
SOURCE:
Supernatural - Wikipedia, the free encyclopedia
su·per·nat·u·ral / ˌsoōpərˈnach(ə
rəl/
adj. (of a manifestation or event) attributed to some force beyond scientific understanding or the laws of nature: a supernatural being.
∎ unnaturally or extraordinarily great: a woman of supernatural beauty.
n. (the supernatural) manifestations or events considered to be of supernatural origin, such as ghosts.
SOURCE: Oxford English Dictionary, 2009
So, your definition is wrong, or at least inaccurate.
So now you are saying that because we don't understand something like a ghost, we shouldn't say it's supernatural or unexplainable???
No, the fact that their existence cannot be tested for or understood by any scientific method and that their existence violates basic laws of biology and physics means that they're supernatural.
Also, it's not a case of "understanding". It's a case of demonstrating their existence - which nobody has ever been able to do. Did you even read my post?
Or are you in the camp that believes that all the supernatural world is simply a figment of the human imagination?
Not just imagination, but wishful thinking, misunderstanding, delusion, gullibility or outright dishonesty. Of course, not all are true of all people, but I find that everyone I know who claims to believe in some aspect of the supernatural does so as a result of one or more of the above.