| self-willed(adjective, determined, resolute, uncompromising, unshakeable) |
| uncompassionate(adjective, animal, mean, hard, tough) |
| unfailing(adjective, certain, unchanging) |
| unfeeling(adjective, animal, mean, hard, tough) |
| unintermitting(continuity, diuturnity) |
| unsparing(adjective, mean, strong, hard, tough) |
| wilful(adjective, determined, resolute, uncompromising, unshakeable) |
| assiduous |
| bound and determined(expression, adjective, idiom, harsh, cruel) |
| brutish(adjective, evil, nasty, harsh, violent) |
| continuing(certain, reliable, trustworthy, endless, boundless) |
| dead set(adjective, determined, resolute, uncompromising, unshakeable) |
| dismal |
| fierce(adjective, animal, mean, hard, tough) |
| forbidding(adjective, close, appearance, strong, hard) |
| ghastly(adjective, appearance, terrible, hopeless) |
| gloomy |
| grisly(adjective, appearance, terrible, hopeless) |
| gruesome(adjective, appearance, terrible, hopeless) |
| inclement(adjective, tough, harsh, cruel, grim) |