1.Definition: having an import not apparent to the senses nor obvious to the intelligence; beyond ordinary understanding

"Mysterious symbols"

Related Adjective(s):mystic, mystical, occult, orphic, secret

2.Definition: of an obscure nature

"The new insurance policy is written without cryptic or mysterious terms", "In its mysterious past it encompasses all the dim origins of life"

Related Adjective(s):cryptic, cryptical, deep, inscrutable, mystifying