| onerous(adjective, hard, great, tough, difficulty) |
| sticky(adjective, hard, difficult, complex, awkward) |
| strenuous(adjective, hard, great, tough, severe) |
| uphill(adjective, hard, great, tough, difficult) |
| wearisome(adjective, hard, tough, severe, difficult) |
| heavy(adjective, tough, severe, difficult, harsh) |
| troublesome(adjective, hard, tough, severe, difficulty) |
| demanding(adjective, hard, tough, severe, difficult) |
| formidable(adjective, tough, severe, difficulty, difficult) |
| grueling(adjective, hard, tough, severe, difficult) |
| wearying(adjective, tough, rough, difficult, heavy) |
| exhausting(adjective, hard, rough, difficult, heavy) |
| gruelling |
| tiring(adjective, hard, tough, severe, rough) |
| effortful(adjective, hard, great, tough, severe) |
| wearing(adjective, hard, tough, rough, difficult) |
| fatiguing(adjective, hard, tough, severe, rough) |
| labored(adjective, hard, great, tough, difficult) |
| ticklish(adjective, difficult) |
| tiresome(adjective, hard, tough, severe, heavy) |