The Collaborative International Dictionary
Insuperableness
Insuperable \In*su"per*a*ble\, a. [L. insuperabilis: cf. OF. insuperable. See In- not, and Superable.] Incapable of being passed over or surmounted; insurmountable; as, insuperable difficulties.
And middle natures, how they long to join,
Yet never pass the insuperable line?
--Pope.
The difficulty is enhanced, or is . . . insuperable.
--I. Taylor.
Syn: Impassable; insurmountable; unconquerable. -- In*su"per*a*ble*ness, n. -- In*su"per*a*bly, adv.
Wiktionary
insuperableness
n. The quality of being insuperable or insurmountable; insuperability.