| difficult(adjective, hard, great, tough, rough) |
| hard(adjective, great, tough, difficult, harsh) |
| laborious(adjective, hard, great, tough, rough) |
| strenuous(adjective, hard, great, tough, rough) |
| arduous(adjective, hard, great, tough, rough) |
| formidable(adjective, tough, severe, difficult, heavy) |
| heavy(adjective, tough, severe, difficult, harsh) |
| labored(adjective, hard, great, tough, rough) |
| onerous(adjective, great, tough, rough, difficult) |
| tough(adjective, great, severe, rough, difficult) |
| severe(adjective, tough, rough, difficult, harsh) |
| backbreaking(adjective, hard, severe, rough, difficult) |
| burdensome(adjective, tough, severe, rough, difficult) |
| uphill(adjective, great, tough, severe, difficult) |
| demanding(adjective, tough, severe, difficult, harsh) |
| forced(adjective, true) |
| knotty(adjective, hard, tough, severe, rough) |
| oppressive(adjective, heavy, burdensome) |
| toilsome(adjective, hard, great, tough, severe) |
| exacting(adjective, tough, severe, difficult, harsh) |