This word is acceptable for play in the US & UK dictionaries that are being used in the following games:

• Lexulous
• Wordscraper
• Wordosaur

adj. Not able to be climbed

adj. incapable of being ascended

adj. incapable of being surmounted or climbed

"El Cap was considered unclimbable, but a mountaineer named Warren Harding was determined to do it."

unpassable    impassable   

unclimbability   

dissolved    chainlink    fog-bound    maintenance-free    snow-topped