| dogged(adjective, mean, strong, hard, tough) |
| fixed(adjective, mean, strong, hard, secure) |
| steadfast(adjective, strong, secure, tough, flat) |
| stony(adjective, person, mean, hard, harsh) |
| set(verb, adjective, strong, determined, resolute) |
| iron(noun, adjective, mean, strong, hard) |
| implacable(adjective, mean, strong, hard, tough) |
| insistent(adjective, determined, resolute, obstinate, unyielding) |
| unshakable(adjective, mean, strong, hard, secure) |
| hard-nosed(adjective, mean, strong, hard, secure) |
| stern(adjective, mean, hard, rough, firm) |
| tenacious(adjective, strong, determined, resolute, persistent) |
| intractable(adjective, hard, tough, firm, determined) |
| mulish(adjective, mean, strong, hard, tough) |
| pigheaded(adjective, mean, hard, tough, deliberate) |
| unbendable(adjective, resist, determined, resolute, obstinate) |
| unwavering(adjective, strong, secure, flat, firm) |
| flinty(adjective, strong, hard, tough, firm) |
| grim(adjective, mean, strong, hard, tough) |
| headstrong(adjective, tough, firm, determined, resolute) |