inscrutable (
http://definr.com/inscrutable)
adj : of an obscure nature; "the new insurance policy is written
without cryptic or mysterious terms"; "a deep dark
secret"; "the inscrutible 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" [syn:
cryptic,
cryptical,
deep,
mysterious,
mystifying]