cryptical -
having a secret or hidden meaning; "cabalistic symbols engraved in stone"; "cryptic writings"; "thoroughly sibylline in most of his pronouncements"- John Gunther
esoteric confined to and understandable by only an enlightened inner circle; "a compilation of esoteric philosophical theories"
cryptical -
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"
inexplicable,
incomprehensible incapable of being explained or accounted for; "inexplicable errors"; "left the house at three in the morning for inexplicable reasons"
