| condensed(verb, adjective, hard, tough) |
| compact(adjective, hard, tough, firm) |
| solid(adjective, hard, tough, firm) |
| close(adjective, hard, tough, slight) |
| concentrated(verb, adjective, hard, tough) |
| dense(adjective, hard, tough, firm) |
| compacted(verb, adjective, strong, hard) |
| hard(adjective, strong, tough, firm) |
| firm(adjective, hard, solid, heavy) |
| packed(verb, adjective, close, strong) |
| impenetrable(adjective, hard, tough, firm) |
| thick(adjective, close, hard, tough) |
| consolidated(adjective, firm, solid, heavy) |
| crowded(verb, adjective, solid, heavy) |
| stiff(adjective, hard, tough, firm) |
| concrete(adjective, hard, tough, firm) |
| heavy(adjective, hard, tough, solid) |
| rigid(adjective, strong, hard, tough) |
| inflexible(adjective, strong, hard, tough) |
| solidified(verb, adjective, hard, tough) |