| pigheaded(adjective, mean, hard, tough, firm) |
| prudish(adjective, tough, correct, severe, firm) |
| unvarying(adjective, set, still, regular, fixed) |
| buckram(adjective, hard, firm, solid, stiff) |
| changeless(adjective, set, severe, firm, still) |
| close-minded(adjective, inflexible) |
| cold(adjective, hard, cool, severe, harsh) |
| correct(adjective, hard, severe, rough, difficult) |
| dense(adjective, set, strong, hard, tough) |
| finicky(adjective, tough, harsh, strict, thorough) |
| frozen(adjective, hard, firm, solid, fixed) |
| fussy(adjective, tough, harsh, strict, particular) |
| headstrong(adjective, tough, firm, unreasonable, inflexible) |
| indurate(adjective, mean, hard, firm, determined) |
| oppressive(adjective, hard, tough, severe, rough) |
| persevering(adjective, tough, firm, determined, unreasonable) |
| pitiless(adjective, severe, harsh, cruel, determined) |
| proper(adjective, hard, correct, severe, rough) |
| reserved |
| stark(adjective, hard, severe, firm, solid) |