| tough(adjective, firm, determined, resolute, obstinate) |
| wayward(adjective, tough, difficult, awkward, obstinate) |
| active |
| brass-bound(adjective, determined, resolute, obstinate, uncompromising) |
| coherent |
| grim(adjective, determined, resolute, uncompromising, unshakeable) |
| hidebound(adjective, determined, resolute, obstinate, uncompromising) |
| inelastic(adjective, determined, resolute, obstinate, uncompromising) |
| peevish(adjective, irritable, crabby, cranky, testy) |
| plodding(adjective, strong, firm, determined, steady) |
| recalcitrant(adjective, tough, firm, difficult, awkward) |
| spirited |
| steady(adjective, strong, firm, determined, resolute) |
| sullen(adjective, mean, irritable, crabby, cranky) |
| uncooperative(adjective, tough, difficult, awkward, obstinate) |
| unflinching(adjective, strong, firm, energetic, determined) |
| unremitting(adjective, strong, firm, energetic, determined) |
| vigorous |
| doctrinaire(adjective, opinionated, dogmatic) |
| attentive(adjective, resolute) |