| stable(adjective, hard, strain, firmness, compact) |
| stiff(adjective, strain, firmness, labour, hardiness) |
| strong(adjective, hard, strain, firmness, compact) |
| firm(adjective, hard, strain, firmness, compact) |
| hard(adjective, strain, firmness, compact, dense) |
| sound(adjective, hard, strain, firmness, compact) |
| substantial(adjective, hard, strain, firmness, compact) |
| durable(adjective, strain, firmness, labour, hardiness) |
| fast(adjective, strain, firmness, labour, hardiness) |
| refractory(adjective, strain, firmness, labour, hardiness) |
| resilient(adjective, strain, firmness, labour, hardiness) |
| stout(adjective, strain, firmness, labour, hardiness) |
| tenable(adjective, strain, firmness, labour, hardiness) |
| tight(adjective, hard, strain, firmness, compact) |
| unyielding(adjective, hard, strain, firmness, compact) |
| hearty |
| sturdy(adjective, hard, compact, dense, rock-hard) |
| able-bodied |
| affectionate |
| antitypous |