The Collaborative International Dictionary of English v.0.48:
Avertible \A*vert"i*ble\, a. Capable of being averted; preventable. [1913 Webster]WordNet (r) 3.0 (2006):
avertible adj 1: capable of being avoided or warded off [syn: evitable, avoidable, avertible, avertable] [ant: inevitable]