Inscrutable /(?)/

In·scru·ta·ble

Inscrutable

a.
  1. 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.
    Waiving a question so inscrutable as this.