Philistinism, analgesia, anesthesia, armor, callosity, callus, coldbloodedness, coldheartedness, coldness, deadness, density, dullness, durity, electronarcosis, flintiness, formidable defenses, hard heart, hard shell, hardenedness, hardheartedness, hardness, hardness of heart, heart of stone, heartlessness, impassibility, impenetrability, impenitence, impenitentness, imperception, imperceptiveness, imperceptivity, impercipience, imperviousness, inconsiderateness, induration, insensibility, insensibleness, insensitiveness, insensitivity, insentience, insolence, inuredness, irrepentance, narcosis, narcotization, nonrepentance, numbness, obduracy, obdurateness, obtuseness, pins and needles, pitilessness, resistance, restiveness, rhinoceros hide, seared conscience, solidity, steeliness, stoniness, thick skin, toughness, unabjectness, uncontriteness, unfeeling, unfeelingness, unmercifulness, unnaturalness, unperceptiveness, unresponsiveness