| strenuous(adjective, hard, tough, severe, rough) |
| diligent(adjective, work, tedious, labour, persevering) |
| formidable(adjective, tough, severe, rough, difficult) |
| assiduous(adjective, work, labour, multitask) |
| onerous(adjective, tough, severe, difficult, awkward) |
| sedulous(adjective, work, labour, multitask) |
| troublesome(adjective, tough, severe, difficult, awkward) |
| wearisome(adjective, tough, severe, difficult, awkward) |
| workaholic |
| busy(adjective, work, labour, multitask) |
| effortful(adjective, tough, severe, difficult, awkward) |
| uphill(adjective, tough, severe, rough, difficult) |
| active |
| delicate(difficult, embarrassing) |
| demanding(adjective, tough, severe, rough, difficult) |
| difficile(adjective, tough, severe, rough, difficult) |
| energetic(adjective, work, labour, multitask) |
| exacting(adjective, tough, severe, rough, difficult) |
| exhausting(adjective, hard, tough, rough, difficult) |
| forced |