Inscrutableness
The Century Dictionary and Cyclopedia
noun.
The character of being inscrutable; inscrutability.
the GNU version of the Collaborative International Dictionary of English
noun.
The quality or state of being inscrutable; inscrutability.
Wiktionary, Creative Commons Attribution/Share-Alike License
noun.
Inscrutability
Word Usage
"It seemed to me that here was the key to her inscrutableness, the clue that if followed properly would make all her strangeness plain."