Synonyms:
cryptic, cryptical, deep, inscrutable, mysterious, mystifying
Meaning: 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"- Rachel Carson; "rituals totally mystifying to visitors from other lands"
Usage examples
He neglected this good advice, and continued his studies; burning minerals and purifying metals one day, and mystifying the Word of God on the next.