Superable

The Latin superābilis, -e may be broadly defined as “possible to overcome,” and falls into two distinct uses within the extant literature:

Of military enemies encampments, regions and territories:

scīlicet ut nōn est per vim superābilis ūllī / clearly, he cannot be overcome by anyone through force (Ovid, Tristia 5.8.27)
murūs superābilies ad dextrā adoriēmur / we will attack the weakened wall at the right

Of diseases and calamities:

caecitās et calivitium opē hūmānā nōndum superābilēs sunt / blindness and baldness cannot yet be cured by human aid

The L&S entry—http://goo.gl/bXJ1UW