| flintiness |
| frugality(noun, cruelty, unkindness, spitefulness, callousness) |
| grimness(ruthlessness, pitilessness, mercilessness, relentlessness) |
| guts |
| ill-temper(noun, cruelty, unkindness, spitefulness, callousness) |
| implacability(ruthlessness, pitilessness, mercilessness, relentlessness) |
| implacableness(ruthlessness, pitilessness, mercilessness, relentlessness) |
| incompliance(ruthlessness, pitilessness, mercilessness, relentlessness) |
| incompliancy(ruthlessness, pitilessness, mercilessness, relentlessness) |
| indomitability(ruthlessness, pitilessness, mercilessness, relentlessness) |
| inexorability(ruthlessness, pitilessness, mercilessness, relentlessness) |
| inexorableness(ruthlessness, pitilessness, mercilessness, relentlessness) |
| infamy(noun, cruelty, unkindness, spitefulness, callousness) |
| inflexibility(ruthlessness, pitilessness, mercilessness, relentlessness) |
| inflexibleness(ruthlessness, pitilessness, mercilessness, relentlessness) |
| iniquity(noun, cruelty, unkindness, spitefulness, callousness) |
| intransigence(ruthlessness, pitilessness, mercilessness, relentlessness) |
| intransigency(ruthlessness, pitilessness, mercilessness, relentlessness) |
| knavishness(noun, cruelty, unkindness, spitefulness, callousness) |
| lack of sympathy(expression, idiom) |