| unquenchable(adjective, empty, gross, avid, greedy) |
| hard(adjective, mean, severe, harsh, cruel) |
| headstrong(adjective, determined, violence, resolute, uncompromising) |
| mortal(adjective, mean, severe, harsh, cruel) |
| omnivorous(adjective, desire, voracious) |
| devouring(adjective, voracious) |
| dogged(adjective, harsh, cruel, determined, fierce) |
| exacting |
| hard-nosed(adjective, cruel, determined, resolute, brutal) |
| inflexible(adjective, harsh, cruel, determined, fierce) |
| insatiate(adjective, avid, greedy, wanting, rapacious) |
| obdurate(adjective, mean, harsh, cruel, determined) |
| pitiless(adjective, mean, severe, harsh, cruel) |
| ravening(adjective, voracious) |
| strict(adjective, harsh, cruel, determined, fierce) |
| unbending(adjective, harsh, cruel, determined, fierce) |
| uncompromising(adjective, harsh, cruel, determined, fierce) |
| unsatisfiable(adjective, avid, greedy, wanting, rapacious) |
| edacious(adjective, desire, voracious) |
| irreconcilable(adjective, hostile, conflicting) |