| unnerving |
| astonishing(adjective, awful, wonderful, amazing, grand) |
| astounding(adjective, great, awful, terrible, grand) |
| fell(adjective, tough, severe, unpleasant, important) |
| forbidding(adjective, appearance, tough, unpleasant, terrible) |
| hairy(adjective, bad, severe, rough, difficult) |
| horrendous(adjective, bad, awful, terrible, shocking) |
| impregnable(adjective, horrible, dreadful, terrifying) |
| petrifying |
| rude(adjective, hard, rough, nasty, cruel) |
| stable(adjective, strong) |
| steep(adjective, great, big, large, long) |
| sticky(adjective, tough, rough, difficult, heavy) |
| stout(adjective, strong) |
| substantial |
| ugly(adjective, bad, hard, tough, severe) |
| complicated(adjective, hard, tough, severe, rough) |
| dark |
| effective(prevailing, influential, commanding) |
| energetic(adjective, strong, prevailing, influential, commanding) |