| arduous(adjective, dull, great, tough, severe) |
| laborious(adjective, dull, hard, great, tough) |
| tough(adjective, action, dull, strong, great) |
| toilsome(adjective, great, tough, severe, difficult) |
| difficult(adjective, dull, hard, great, tough) |
| hard(adjective, dull, great, tough, severe) |
| active(adjective, action, strong, tough, difficult) |
| exhausting(adjective, dull, hard, difficult, awkward) |
| energetic(adjective, action, strong, tough, smart) |
| onerous(adjective, dull, great, tough, difficult) |
| vigorous(adjective, action, strong, tough, smart) |
| burdensome(adjective, dull, tough, severe, difficult) |
| demanding(adjective, dull, hard, tough, severe) |
| tiring(adjective, dull, tough, difficult, full) |
| eager(adjective, activity, difficult, energetic, determined) |
| spirited(adjective, strong, tough, difficult, energetic) |
| zealous(adjective, activity, strong, tough, smart) |
| dynamic(adjective, action, strong, tough, smart) |
| taxing(adjective, difficult) |
| animated(adjective, strong, moving, difficult, energetic) |