| stoical(adjective, calm, cool, steady, tranquil) |
| strict(adjective, tough, severe, firm, harsh) |
| substantial(adjective, strong, sound, tough, solid) |
| tactless(adjective, hard, indifferent, unkind, unresponsive) |
| tenacious(adjective, strong, hard, sound, tough) |
| thick-skinned(adjective, calm, hard, cool, tough) |
| tough as nails(expression, adjective, idiom, strong, hard) |
| unaffected(adjective, calm, cool, steady, tranquil) |
| unashamed(adjective, unfeeling, callous, unbending, toughened) |
| unbending(adjective, strong, hard, tough, fixed) |
| uncompromising(adjective, tough, firm, fixed, distant) |
| unconcerned(adjective, hard, indifferent, unkind, unresponsive) |
| undisturbed(adjective, calm, cool, steady, tranquil) |
| unexcitable(adjective, calm, cool, steady, unaffected) |
| unfeeling(adjective, hard, tough, rough, harsh) |
| unflappable(adjective, calm, cool, steady, unaffected) |
| unflexible(adjective, tough, firm, stiff, distant) |
| unkind(adjective, hard, tough, harsh, indifferent) |
| unmoved(adjective, calm, cool, steady, unresponsive) |
| unrelenting(adjective, tough, firm, harsh, cruel) |