unscalable
- a incapable of being ascended
- Among the unscalable peaks of the staggering, snow-locked Himalayas is a dreary region glamorously called "The Roof of the World.
- Virtually every branch of science is surrounded by beetling walls of unscalable figures.
- His seven-party coalition has surprised many by conquering two of the unscalable peaks in Japanese politics: opening the rice market and passing laws to reform the electoral system.