| immobile(adjective, secure, intense, steady, fixed) |
| inconvincible(adjective, determined, resolute, uncompromising, unshakeable) |
| indifferent(adjective, cold, unyielding, rocky, pebbly) |
| indurate(adjective, mean, hard, resolute, inflexible) |
| oak |
| pitiless(adjective, mean, harsh, cruel, determined) |
| rock |
| ruthless(adjective, mean, hard, rough, harsh) |
| self-opinionated(adjective, determined, resolute, uncompromising, unshakeable) |
| stone |
| stony-hearted |
| strong(adjective, hard, tough, flat, firm) |
| stubborn as a mule(expression, adjective, idiom, resist, persistence) |
| unadaptable(adjective, hard, resolute, rigid, inflexible) |
| unchanging |
| uncompassionate(adjective, person, mean, hard, feelings) |
| ungiving(adjective, firm, stiff, unyielding, militant) |
| wayward(adjective, persistent, obstinate, insistent, dogged) |
| aloof(adjective, fixed, rigid, inflexible, obdurate) |
| bigoted(adjective, determined, resolute, obstinate, uncompromising) |