| rigid(adjective, hard, tough, severe, difficult) |
| severe(adjective, hard, tough, difficult, painful) |
| stiff(adjective, hard, tough, severe, difficult) |
| strenuous(adjective, hard, tough, severe, difficult) |
| titanesque(adjective, big, large, grand, huge) |
| toilsome(adjective, hard, tough, severe, difficult) |
| tough(adjective, hard, severe, difficult, painful) |
| trying(adjective, hard, tough, severe, difficult) |
| unyielding(adjective, hard, tough, severe, difficult) |
| uphill(adjective, hard, tough, severe, difficult) |
| upstream(adjective, hard, tough, severe, difficult) |
| wearisome(adjective, hard, tough, severe, difficult) |
| august(adjective, big, large, huge, unusually) |
| ball of fire(expression, adjective, idiom, strong, energetic) |
| barn door(expression, large, huge, vast, immense) |
| bullish(adjective, strong, energetic, violent, powerful) |
| cavernous(adjective, big, large, huge, unusually) |
| cogent(adjective, strong, energetic, violent, powerful) |
| coming on strong(expression, adjective, idiom, strong, energetic) |
| commanding(adjective, strong, energetic, violent, powerful) |