| closed |
| contrary(adjective, determined, resolute, obstinate, uncompromising) |
| crisp(adjective, tough, firm, fixed, distant) |
| distant(adjective, tough, firm, fixed, rigid) |
| do or die(expression, adjective, idiom, tough, firm) |
| dogged(verb, adjective, set, hard, stiff) |
| dug in(expression, adjective, tough, firm, distant) |
| dyed-in-the-wool(hard, resolute, rigid, inflexible, strict) |
| formal(adjective, tough, firm, fixed, distant) |
| hanging(adjective, determined, resolute, obstinate, uncompromising) |
| hard(firm, resolute, rigid, inflexible, strict) |
| hard-and-fast(adjective, set, hard, stiff, rigid) |
| hard as nails(expression, adjective, idiom, tough, firm) |
| hardheaded(adjective, determined, resolute, obstinate, uncompromising) |
| hold the fort(expression, adjective, idiom, tough, firm) |
| hold the line(expression, adjective, idiom, tough, firm) |
| immutable(adjective, set, hard, stiff, rigid) |
| impervious |
| implacable(adjective, hard, firm, determined, resolute) |
| incompliant(adjective, tough, firm, fixed, distant) |