| burdensome(adjective, hard, difficult, heavy, complex) |
| tough(adjective, hard, severe, rough, difficult) |
| hard(adjective, tough, severe, rough, difficult) |
| laborious(adjective, hard, severe, rough, difficult) |
| arduous(adjective, hard, tough, severe, rough) |
| difficult(adjective, hard, tough, rough, harsh) |
| trying(verb, adjective, hard, tough, severe) |
| severe(adjective, hard, tough, difficult, harsh) |
| oppressive(adjective, hard, difficult, heavy, complex) |
| weighty(adjective, hard, difficult, heavy, complex) |
| serious(adjective, hard, difficult, heavy, complex) |
| backbreaking(adjective, hard, difficult, heavy, complex) |
| grievous(adjective, hard, severe, difficult, complex) |
| punishing(adjective, hard, difficult, complex) |
| toilsome(adjective, hard, difficult, complex, laborious) |
| ambitious(adjective, hard, difficult, complex) |
| painful(adjective, hard, difficult, complex) |
| rough(adjective, hard, difficult, heavy, complex) |
| rugged(adjective, hard, difficult, complex, rigorous) |
| demanding(adjective, hard, tough, severe, rough) |