mysterious vs mystery

mysterious is not a noun while mystery is a noun.

Word	Noun	Adjective	Verb	Adverb
mysterious	No	Yes	No	No
mystery	Yes	No	No	No

mysterious (noun)	mystery (noun)
	something that baffles understanding and cannot be explained
	a story about a crime (usually murder) presented as a novel or play or movie

mysterious (adjective)	mystery (adjective)
having an import not apparent to the senses nor obvious to the intelligence; beyond ordinary understanding
of an obscure nature