What does "inscrutable" mean?

Inscrutable: Unsearchable; incapable of being searched into and understood by inquiry or study; impossible or difficult to be explained or accounted for satisfactorily; obscure; incomprehensible; as, an inscrutable design or event. 'T is not in man To yield a reason for the will of Heaven Which is inscrutable. Beau. & Fl. Waiving a question so inscrutable as this. De Quincey.