Of or pertaining to mystery; containing a mystery; difficult or impossible to understand; obscure; not revealed or explained; enigmatical; incomprehensible.
source: Webster 1913
adjective satellite
of an obscure nature
The new insurance policy is written without cryptic or mysterious terms. A deep dark secret. The inscrutable workings of Providence. In its mysterious past it encompasses all the dim origins of life. Rituals totally mystifying to visitors from other lands.
source: WordNet 3.0
having an import not apparent to the senses nor obvious to the intelligence; beyond ordinary understanding
Mysterious symbols. The mystical style of Blake. Occult lore. The secret learning of the ancients.