Impassible

(a.) Not subject to harm or pain; unfeeling, or not showing feeling; without sensation.

Thesaurus Entries

Mickey Finn, Pentothal, alleviating, alleviative, analgesic, anodyne, assuasive, balmy, balsamic, benumbing, cathartic, chloroform, cleansing, cocaine, deadening, demulcent, dope, drug, dull, dulling, easing, emollient, ether, ethyl chloride, ethylene, gas, hard, hypnotic, impassible, impenetrable, impermeable, impervious, insensate, insensitive, knockout drop, lenitive, lullaby, mandrake, menthol, mitigating, mitigative, morphia, morphine, narcotic, nightcap, nitrous oxide, numbing, obtuse, opiate, opium, pain-killer, pain-killing, palliative, poppy, purgative, relieving, remedial, rocky, sedative, sleep-bringer, sleep-inducer, sleep-producer, sleeping pill, softening, somnifacient, soothing, soporific, stunning, stupefying, subduing, tranquilizer