- a incapable of being ascended
- s incapable of being surmounted or climbed
- For years, K-2 has been regarded as unclimbable.
- Two days later, the rescue attempt was called off due to bad weather and the difficulties involved in climbing an almost unclimbable mountain in the hopes of finding Prez alive.
- An "unclimbable" fence will be erected to in-close a compound.