(n.) The quality or condition of being impassible; insusceptibility of injury from external things.

abatement allayment alleviation anesthesia anesthetizing anxiety equivalent appeasement assuagement callousness deadening deadness depraved appetite diminishment diminution dulling dullness ease easement easing electronarcosis impassibility imperception imperceptiveness imperceptivity impercipience inconsiderateness insensibility insensibleness insensitiveness insensitivity insentience lessening lulling mitigation mollification narcosis narcotization neurasthenia numbing numbness obtuseness palliation paresthesia parorexia pica pins and needles reduction relief remedy salving softening soothing speech abnormality subduement thick skin unfeeling unfeelingness unperceptiveness