| inanimate(adjective, hard, tough, severe, cold) |
| inattentive |
| incompassionate |
| inconsiderate |
| indurate(adjective, mean, hard, tough, harsh) |
| indurated(adjective, hard, careless, indifferent, cruel) |
| insensate(adjective, hard, tough, severe, careless) |
| insensible(adjective, hard, tough, severe, careless) |
| insentient(adjective, hard, careless, indifferent, cruel) |
| intolerant(adjective, hard, tough, harsh, cold) |
| intractable |
| inured(adjective, hard, careless, indifferent, cruel) |
| iron(adjective, mean, hard, tough, harsh) |
| iron-hearted(adjective, hard, tough, severe, cold) |
| irreverent(adjective, hard, unfeeling, unsympathetic, hardened) |
| laid-back(adjective, detached, impassive, unresponsive, reticent) |
| listless(adjective, calm, dull, flat, detached) |
| malevolent(adjective, evil, negative) |
| marble(adjective, detached, impassive, unresponsive, insensitive) |
| matter-of-fact(adjective, calm, cold, cruel, unfeeling) |