97 Moby Thesaurus words for "case hardened": Philistine, acclimated, acclimatized, accommodated, accustomed, adapted, adjusted, backed, balking, balky, bigoted, brazen, bulldogged, bulletheaded, bullheaded, calcified, callous, calloused, conditioned, conscienceless, crusted, crusty, crystallized, dogged, dogmatic, experienced, familiarized, fanatic, flinty, fossilized, granulated, hard, hardened, hardheaded, hardhearted, headstrong, heartless, hornified, impervious, incrusted, indurate, indurated, insensitive, intolerant, inured, lapidified, lost to shame, mulish, naturalized, obdurate, obstinate, opinionated, orientated, oriented, ossified, overzealous, pachydermatous, persevering, pertinacious, petrified, pigheaded, proof against, reinforced, restive, rigidified, run-in, sclerotic, seared, seasoned, self-willed, set, shameless, solidified, steeled, steeled against, steely, stiff-necked, stiffened, stony, strengthened, strong-willed, strongheaded, stubborn, sulky, sullen, tenacious, thick-skinned, toughened, trained, unblushing, uncooperative, unregenerate, used to, vitrified, willful, wont, wonted

Source: Moby Thesaurus II by Grady Ward, 1.0