Adjective: unclimbable ,ún'klI-mu-bul
- Incapable of being ascended
"The sheer cliff face proved unclimbable for the novice climbers";
- unscalable
- Incapable of being surmounted or climbed
"The unclimbable peak had never been conquered";
- unsurmountable
See also: impassable, unpassable
Antonym: scalable