| tough(adjective, severe, rough, difficult, painful) |
| tricky(adjective, difficult, awkward, demanding, grueling) |
| uphill(adjective, tough, severe, rough, difficult) |
| abstruse |
| ambitious(adjective, tough, severe, painful, problematic) |
| awkward(adjective, difficult, demanding, grueling, problematical) |
| backbreaker(adjective, tough, severe, painful, problematic) |
| backbreaking(adjective, tough, rough, difficult, heavy) |
| bothersome(adjective, tough, severe, rough, difficult) |
| brutal |
| burdensome(adjective, tough, severe, rough, difficult) |
| challenging(adjective, tough, severe, difficult, awkward) |
| complex |
| complicated(adjective, tough, rough, difficult, heavy) |
| crucial(adjective, tough, severe, painful, problematic) |
| delicate |
| distressing(adjective, tough, rough, difficult, heavy) |
| easier said than done(expression, adjective, tough, severe, painful) |
| effortful(adjective, tough, severe, rough, difficult) |
| exhausting(adjective, tough, rough, difficult, heavy) |