The Collaborative International Dictionary of English v.0.48:

Insurable \In*sur"a*ble\, a. [From Insure.]
   Capable of being insured against loss, damage, death, etc.;
   proper to be insured.
   [1913 Webster]

         The French law annuls the latter policies so far as
         they exceed the insurable interest which remained in
         the insured at the time of the subscription thereof.
                                                  --Walsh.
   [1913 Webster]

WordNet (r) 3.0 (2006):

insurable
    adj 1: capable of being insured or eligible to be insured