mystery vs mysterious

mystery is a noun but mysterious is not a noun.

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

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

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