| unyielding(adjective, set, hard, sound, tough) |
| large(adjective, feature, characteristic, person, body) |
| sturdy(adjective, calm, person, body, strong) |
| fast(adjective, calm, secure, tough, continue) |
| impregnable(adjective, sound, reasonable, strain, rational) |
| resilient(adjective, tough, strain, determined, stiff) |
| big(adjective, feature, characteristic, person, body) |
| rigid(adjective, hard, tough, strain, firm) |
| lasting(adjective, strain, firmness, labour, hardiness) |
| permanent(adjective, strain, firmness, labour, hardiness) |
| tough(adjective, calm, person, body, hard) |
| tight(adjective, close, hard, secure, tough) |
| well-established(adjective, strain, firmness, distinct, labour) |
| resistant(adjective, tough, strain, fit, healthy) |
| abundant(adjective, strain, firmness, greatness, labour) |
| invariable(adjective, strain, firmness, labour, hardiness) |
| potent(adjective, good, clear, great, sound) |
| huge(adjective, feature, characteristic, person, body) |
| proof(adjective, strain, firmness, labour, hardiness) |
| refractory(adjective, strain, firmness, labour, hardiness) |