| exacting(adjective, tough, severe, firm, harsh) |
| exhortatory |
| firm(adjective, strong, hard, tough, severe) |
| flinty(adjective, strong, hard, tough, severe) |
| forbidding(adjective, strong, hard, tough, severe) |
| frowning(adjective, strong, hard, tough, severe) |
| grim(adjective, strong, hard, tough, severe) |
| grueling |
| gruelling |
| hang-tough(adjective, strong, hard, tough, severe) |
| hard(adjective, strong, tough, severe, firm) |
| hard-boiled(adjective, strong, hard, tough, severe) |
| hard-core(adjective, strong, hard, tough, severe) |
| hard-line(adjective, strong, hard, tough, severe) |
| hard-nosed(adjective, strong, hard, tough, severe) |
| hard-shell(adjective, strong, hard, tough, severe) |
| hardheaded(adjective, strong, hard, tough, severe) |
| harsh(adjective, strong, hard, tough, severe) |
| hortatory |
| illuminating |