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. [ 1913 Webster ]
Secure of death, I should contemn thy dart
Though naked, and impassible depart. Dryden. [ 1913 Webster ]
n. Impassibility. [ 1913 Webster ]