[ noun ] the quality of being impossible to investigate <noun.attribute> the inscrutability of the future
Inscrutability \In*scru`ta*bil"i*ty\, n. The quality or state of being inscrutable; inscrutableness.
As Mr Sloane, who seduces them both, young Ian Pepperell (though physically too slight) has the right inscrutability, but not nearly enough skill in nuance.