The Collaborative International Dictionary of English v.0.48:
Climbable \Climb"a*ble\, a. Capable of being climbed. [1913 Webster]WordNet (r) 3.0 (2006):
climbable adj 1: capable of being ascended [syn: ascendable, ascendible, climbable] 2: capable of being surmounted [syn: surmountable, climbable]