| ferocity(noun, cruelty, harshness, unkindness, coldness) |
| flintiness |
| grimness(ruthlessness, mercilessness, relentlessness) |
| hard-heartedness(noun, cruelty, harshness, unkindness, callousness) |
| implacability(ruthlessness, mercilessness, relentlessness) |
| implacableness(ruthlessness, mercilessness, relentlessness) |
| incompliance(ruthlessness, mercilessness, relentlessness) |
| incompliancy(ruthlessness, mercilessness, relentlessness) |
| indomitability(ruthlessness, mercilessness, relentlessness) |
| inflexibleness(ruthlessness, mercilessness, relentlessness) |
| inhuman treatment(expression, idiom) |
| insensibility(noun, cruelty, harshness, unkindness, callousness) |
| insensitiveness(noun, cruelty, harshness, unkindness, callousness) |
| intransigence(ruthlessness, mercilessness, relentlessness) |
| intransigency(ruthlessness, mercilessness, relentlessness) |
| lack of feeling(expression, idiom) |
| lack of sympathy(expression, idiom) |
| malice(noun, cruelty, harshness, unkindness, callousness) |
| maliciousness(cruelty, coldness, callousness, hardheartedness) |
| masochism(noun, cruelty, harshness, unkindness, callousness) |