| effortful(adjective, hard, great, tough, rough) |
| fatiguing(adjective, dull, difficult, awkward, boring) |
| lively(adjective, action, strong, tough, energetic) |
| operose(adjective, hard, tough, severe, rough) |
| peppy(adjective, action, strong, tough, informal) |
| powerful(adjective, strong, great, tough, difficult) |
| resolute(adjective, activity, energetic, zealous) |
| sedulous(adjective, thorough, meticulous, painstaking) |
| vital(adjective, strong, tough, intense, energetic) |
| aggressive(adjective, strong, energetic, lively, active) |
| ardent(adjective, difficult, energetic, active, vigorous) |
| assiduous(adjective, thorough, meticulous, painstaking) |
| backbreaking(adjective, strong, hard, rough, difficult) |
| brisk(adjective, action, strong, tough, intense) |
| diligent(adjective, thorough, meticulous, painstaking) |
| grueling(adjective, hard, tough, severe, difficult) |
| keen |
| kinetic(adjective, action, strong, moving, energetic) |
| oppressive(adjective, dull, difficult, harsh, cruel) |
| rough(adjective, action, hard, great, tough) |