| stuffy(adjective, tough, correct, moderate, severe) |
| taut(adjective, hard, firm, solid, stiff) |
| undeviating(adjective, severe, harsh, cruel, determined) |
| stony(adjective, set, hard, firm, solid) |
| brassbound(adjective, resist, determined, resolute, persistent) |
| frigid(adjective, cool, cold, detached, unfriendly) |
| hardheaded(adjective, strong, hard, tough, determined) |
| narrow-minded(adjective, persistent, obstinate, insistent, dogged) |
| pat(adjective, firm, determined, usual, regular) |
| pertinacious(adjective, tough, determined, resolute, obstinate) |
| single-minded(adjective, tough, severe, firm, harsh) |
| static(adjective, set, secure, severe, still) |
| callous(adjective, set, mean, strong, hard) |
| conventional(adjective, correct, proper, usual, straight) |
| critical(adjective, severe) |
| cruel(adjective, strong, hard, tough, severe) |
| dour(adjective, hard, tough, severe, firm) |
| hard-line(adjective, strong, hard, tough, severe) |
| immutable(adjective, set, hard, regular, fixed) |
| painstaking |