1. (n.) The quality or state of being hard, literally or figuratively.

2. (n.) The cohesion of the particles on the surface of a body, determined by its capacity to scratch another, or be itself scratched;-measured among minerals on a scale of which diamond and talc form the extremes.

3. (n.) The peculiar quality exhibited by water which has mineral salts dissolved in it. Such water forms an insoluble compound with soap, and is hence unfit for washing purposes.

Philistinism abstruseness arduousness armor asperity astringency austerity bothersomeness burdensomeness callosity callousness callus closeness cohesiveness coldbloodedness coldheartedness coldness compactness complexity complication congestedness congestion consistence consistency crabbedness crampedness crowdedness cruelty deepness denseness density difficultness difficulty durability esoterica firmness flintiness formidable defenses fundamentalism gluiness grimness hairiness hard heart hard shell hardenedness hardheartedness hardiness hardness of heart hardship harshness heart of stone heartlessness impenetrability impenitence impenitentness impermeability imperviousness impliability imporosity inclemency incompressibility induration inexorability inexorableness inflexibility infrangibility insensitiveness insensitivity insolence intricacy inuredness irrepentance jammedness knottiness laboriousness lastingness leatherlikeness mercilessness nonrepentance obduracy obdurateness obstinacy onerousness oppressiveness orthodoxy pitilessness precisianism profoundness profundity purism puritanism reconditeness relative density relentlessness remorselessness resistance rhinoceros hide rigidity rigidness rigor rigorousness ropiness roughness ruggedness ruthlessness seared conscience severity short shrift solidity solidness soundness specific gravity spissitude stability stamina staunchness sternness stiffness stoniness stoutness strength strenuousness stringency stringiness stubbornness sturdiness temper tenacity tender mercies thick skin thickness toilsomeness toughness troublesomeness unabjectness unbendingness unbreakability unbreakableness uncompassionateness uncompromisingness uncontriteness unfeeling unfeelingness unforgivingness ungentleness unmercifulness unnaturalness unrelentingness unremorsefulness unresponsiveness unsympatheticness unyieldingness vicissitude vigor viscidity viscosity viscousness vitality