| flinty |
| impassible(hard, insensitive, unsusceptible) |
| imperturbable(adjective, calm, cool, restrained, steady) |
| indurated(adjective, hard, careless, indifferent, cruel) |
| inhuman(adjective, hard, tough, severe, cruel) |
| insentient(adjective, hard, careless, indifferent, cruel) |
| rocky |
| seasoned(adjective, hard, unfeeling, unsympathetic, hardened) |
| soulless(adjective, hard, careless, indifferent, cruel) |
| thick-witted |
| uncompassionate(adjective, mean, hard, tough, severe) |
| unconcerned(adjective, calm, hard, careless, indifferent) |
| unkind(adjective, hard, tough, severe, harsh) |
| unmoved(adjective, calm, cool, restrained, steady) |
| unresponsive(adjective, calm, hard, careless, indifferent) |
| unsparing(adjective, tough, harsh, grim, painful) |
| above(adjective, indifferent, detached, distant, remote) |
| ace |
| adamant(adjective, mean, hard, tough, harsh) |
| adventurer |