Impassible
Impassible , adjective
[Latin impassibilis; pref. im- not + passibilis passable: compare French 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.
Secure of death, I should contemn thy dart
Though naked, and impassible depart.