• WordNet 3.6
    • adj unsurmountable incapable of being surmounted or climbed
    • adj unsurmountable not capable of being surmounted or overcome "insurmountable disadvantages"
    • ***
Webster's Revised Unabridged Dictionary
    • a Unsurmountable Insurmountable.
    • ***
Chambers's Twentieth Century Dictionary
    • adj Unsurmountable un-sur-mown′ta-bl insurmountable.
    • ***


In literature:

He also considers the difficulties of a journey to Germany under the present conditions to be almost unsurmountable.
"The Coming Conquest of England" by August Niemann
A great, unsurmountable wall seemed to obstruct Ellen's thought.
"To the Last Man" by Zane Grey
One difficulty confronted him, and until he had mentioned it to Hogan seemed unsurmountable he had need of a ship.
"The Tavern Knight" by Rafael Sabatini
The ignorant man sees only the unsurmountable wall of death, hiding, seemingly forever, his cherished friends.
"Autobiography of a YOGI" by Paramhansa Yogananda
This war is gradually crumbling the once unsurmountable wall of caste.
"Over The Top" by Arthur Guy Empey
But what ground was now unsurmountable to Roman valour?
"The History of Rome; Books Nine to Twenty-Six" by Titus Livius
He had not been at Frankfort a year before he had learnt to look on this hostility of Austria as unsurmountable.
"Bismarck and the Foundation of the German Empire" by James Wycliffe Headlam
Then they reached a large stream with an almost unsurmountable mountain to the west.
"A Backward Glance at Eighty" by Charles A. Murdock
That's an unsurmountable objection at the start.
"Big Game" by Mrs. George de Horne Vaizey
In water-leg boilers, the use of such flat-stayed surfaces under pressure presents difficulties that are practically unsurmountable.
"Steam, Its Generation and Use" by Babcock & Wilcox Co.
One almost unsurmountable obstacle lies in the uncanny grip that the "medicine man" wields in all the tribes.
"An African Adventure" by Isaac F. Marcosson
This appears to me to be an unsurmountable difficulty.
"The Peace Negotiations" by J. D. Kestell
He hoped, too, that some physical impossibility, some unsurmountable difficulty, would compel him to give up his plan.
"The Voyages and Adventures of Captain Hatteras" by Jules Verne
Others than he would at once be confronted with an unsurmountable difficulty.
"Cooking and Dining in Imperial Rome" by Apicius
The difficulty of broaching the subject to his equerry struck him as unsurmountable.
"Majesty" by Louis Couperus
Though Louis met almost unsurmountable obstacles later in life, he was able to rejoice, having enjoyed a sunny childhood.
"Famous Men of Science" by Sarah K. Bolton
The black pearl was his object, but the difficulties to be overcome in endeavouring to secure it were almost unsurmountable.
"The Second String" by Nat Gould
It was a serious position and seemed well night unsurmountable.
"A Century of Sail and Steam on the Niagara River" by Barlow Cumberland
Obviously the fence was unsurmountable.
"Under One Flag" by Richard Marsh
Between them there existed a wide barrier of birth that was of necessity unsurmountable.
"Her Royal Highness" by William Le Queux

In science:

The difficult for users to share long streams of secret keys beforehand has been an unsurmountable barrier preventing widespread use of one-time pad systems.
Secure sharing of random bits over the Internet
With enough work, in the near future we should be able to establish that either the diverse goals of the program can in fact be met or that the program encounters specific unsurmountable obstacles.
Overview and Outlook
However, it has not run into an unsurmountable obstacle either.
Overview and Outlook
The unsurmountable problems encountered in an ensemble interpretation of the wave function (or of any other superposition, such as |ai + |bi) are reflected by the fact that there is no ensemble entropy that would represent the unknown property-to-be-measured (see the first step of Fig. 2.2 or 2.3 – cf. also Zurek 1984).
Decoherence: Basic Concepts and Their Interpretation
At the moment we failed to derive the analogous expression for almost-symmetric (slightly asymmetric) real random matrices due to unsurmountable technical problems.
Almost-Hermitian Random Matrices: Eigenvalue Density in the Complex Plane
Within their framework, however, the barrier ln N appeared unsurmountable, and some crucial new ideas were needed.
Hopfield models as generalized random mean field models
It was apparently the fears to find unsurmountable difficulties in this problem which deterred further research on spherical GW antennas for years .
The detection of Gravitational Waves
In any case, subtle is the time in quantum mechanics! The idea of an event happening at a given time plays a crucial role in quantum theory [110] and at first sight introduces unsurmountable difference between space and time.
Zeno meets modern science
Since the horizon implies a classically unsurmountable barrier to our ability to see what lies beyond it, it is natural to attach an entropy to the horizon size (i.e., to its area) for it is a measure of our ignorance about what is going on in the other side.
Relic gravitational waves in the expanding Universe
In Ref. , I generalized this expression to inhomogeneous zeta functions (most important for physical applications), but staying always in two dimensions, for this was commonly believed to be an unsurmountable restriction of the original formula (see, e.g., Ref. ).
Zeta function regularization in Casimir effect calculations and J.S. Dowker's contribution
Ukawa at the international Lattice conference in 2001 , in a presentation including a famous plot of the computational costs, which looked like an unsurmountable barrier, and was henceforth dubbed “the Berlin wall” of lattice QCD.
SU(N) gauge theories at large N
The above difficulties are no unsurmountable problems.
Some thoughts and some new results about the Butcher-Oemler effect