| inexorable(adjective, characteristic, mean, strong, hard) |
| unyielding(adjective, characteristic, mean, strong, hard) |
| firm(noun, adjective, mean, strong, hard) |
| rigid(adjective, mean, strong, hard, tough) |
| adamant(adjective, mean, strong, hard, strength) |
| stubborn(adjective, characteristic, quality, mean, strong) |
| obdurate(adjective, strong, hard, tough, firm) |
| steel(adjective, strong, hard, strength, tough) |
| inflexible(adjective, mean, strong, hard, tough) |
| hard(noun, adjective, characteristic, mean, strong) |
| press(verb, activity, hold, calm, quiet) |
| relentless(adjective, mean, strong, hard, tough) |
| unrelenting(adjective, mean, hard, tough, resist) |
| grey(dull, lead, leaden, mousy, steely) |
| unbending(adjective, mean, strong, hard, tough) |
| gray(adjective, dull, silver, leaden, steely) |
| implacable(adjective, mean, strong, hard, tough) |
| uncompromising(adjective, mean, hard, resist, determined) |
| weapon(noun, piece, heat, arm, firearm) |
| adamantine(adjective, set, strong, hard, tough) |