Synonyms: unclimbable, unsurmountable
Definition: incapable of being surmounted or climbed
Similar words: unpassable, impassable
Definition: incapable of being passed
Synonyms: unsurmountable, insurmountable
Definition: not capable of being surmounted or overcome
Usage: insurmountable disadvantages
Similar words: insuperable, unconquerable
Definition: incapable of being surmounted or excelled
Usage: insuperable odds; insuperable heroes