Synonyms and related words :
Philistine, backed, calcified, callous, calloused, case-hardened, crusted, crusty, crystallized, flinty, fossilized, granulated, hard, hardened, hardhearted, hornified, impervious, incrusted, indurate, indurated, insensitive, inured, lapidified, ossified, pachydermatous, petrified, proof against, reinforced, rigidified, sclerotic, set, solidified, steeled against, steely, stiffened, stony, strengthened, thick-skinned, toughened, vitrified