| merciless(adjective, person, mean, hard, tough) |
| relentless(adjective, mean, hard, tough, severe) |
| pitiless(adjective, person, mean, hard, tough) |
| ruthless(adjective, mean, hard, tough, severe) |
| inexorable(adjective, mean, hard, tough, severe) |
| unrelenting(adjective, mean, hard, tough, severe) |
| cruel(adjective, mean, hard, severe, rough) |
| harsh(adjective, mean, hard, tough, severe) |
| implacable(adjective, mean, hard, tough, severe) |
| hard(adjective, mean, tough, severe, rough) |
| grim(adjective, mean, hard, tough, severe) |
| unsympathetic(adjective, person, mean, severe, harsh) |
| stern(adjective, mean, hard, severe, rough) |
| brutal(adjective, person, mean, hard, severe) |
| uncompassionate(adjective, person, mean, feelings, unkind) |
| unfeeling(adjective, person, mean, severe, harsh) |
| unmerciful(adjective, mean, hard, tough, severe) |
| unappeasable(adjective, mean, severe, harsh, cruel) |
| adamant(adjective, person, mean, hard, rough) |
| heartless(adjective, mean, hard, severe, harsh) |