The Collaborative International Dictionary
Unsurmountable \Un`sur*mount"a*ble\, a.
Insurmountable.
--Locke.
Douglas Harper's Etymology Dictionary
"incapable of being overcome," 1701, from un- (1) "not" + surmountable.
Wiktionary
a. insurmountable
WordNet
adj. not capable of being surmounted or overcome; "insurmountable disadvantages" [syn: insurmountable] [ant: surmountable]
impossible to surmount or climb [syn: unclimbable]
Usage examples of "unsurmountable".
He felt a bullet pluck at the sleeve of his coat, the three-foot bank that he had to scale with his aching leg and the woman in his arms loomed as an unsurmountable obstacle in his mind, then a great pair of hands caught him from behind and he was standing on top of the bank, still clutching the woman before he had more than dimly realised what was happening.
Strauss, who, in the pig-headed fashion of considerable Americans, despite seemingly unsurmountable and political difficulties and the assurances of his architectural colleagues that his dream was a technical impossibility, just went ahead and built it anyway.
I had surmounted seemingly unsurmountable obstacles and I had reached my goal.
His illegitimacy should have been an unsurmountable barrier, but even at a young age Niall had been tall and proud, intelligent, cunning, ruthless, a born leader.
I felt his unsurmountable strength beneath the fabric, the strange, unnatural fabric.