Source : Webster's Revised Unabridged Dictionary (1913)

Impassible \Im*pas"si*ble\, a. [L. impassibilis; pref. im- not +
   passibilis passable: cf. F. impassible. See {Passible}.]
   Incapable of suffering; inaccessible to harm or pain; not to
   be touched or moved to passion or sympathy; unfeeling, or not
   showing feeling; without sensation. ``Impassible to the
   critic.'' --Sir W. Scott.

         Secure of death, I should contemn thy dart Though
         naked, and impassible depart.            --Dryden.