| hardened(verb, adjective, hard, cool, firm) |
| inured(adjective, hard, careless, indifferent, cruel) |
| toughened(verb, adjective, hard, careless, indifferent) |
| callous(adjective, hard, cool, firm, cruel) |
| impassive(adjective, hard, cool, careless, indifferent) |
| set(verb, adjective, strong, hard, firm) |
| stiffened |
| case-hardened(adjective, hard, careless, indifferent, cruel) |
| firm(adjective, set, strong, hard, stiff) |
| hard(adjective, set, strong, firm, careless) |
| hardhearted(adjective, hard, careless, indifferent, cruel) |
| heartless(adjective, hard, cool, careless, indifferent) |
| indurate(adjective, set, strong, hard, firm) |
| inflexible(adjective, set, strong, hard, firm) |
| insensible(adjective, hard, cool, careless, indifferent) |
| insensitive(adjective, hard, careless, indifferent, cruel) |
| inveterate(adjective, established) |
| obdurate(adjective, hard, careless, indifferent, cruel) |
| rigid(adjective, set, strong, hard, firm) |
| steeled(verb, adjective, set, hard, unfeeling) |