The Collaborative International Dictionary of English v.0.48:

Inhabitable \In*hab"it*a*ble\, a. [L. inhabitabilis. See
   Inhabit.]
   Capable of being inhabited; habitable.
   [1913 Webster]

         Systems of inhabitable planets.          --Locke.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Inhabitable \In*hab"it*a*ble\, a. [L. inhabitabilis: cf. F.
   inhabitable. See In- not, and Habitable.]
   Not habitable; not suitable to be inhabited. [Obs.]
   [1913 Webster]

         The frozen ridges of the Alps
         Or other ground inhabitable.             --Shak.
   Inhabitance

WordNet (r) 3.0 (2006):

inhabitable
    adj 1: fit for habitation; "the habitable world" [syn:
           habitable, inhabitable]