| sophisticated(adjective, hard, difficult, complex, intelligent) |
| backbreaking(adjective, hard, difficult, complex) |
| complicated(adjective, hard, difficult, complex) |
| heartrending(adjective, hard, difficult, intense, complex) |
| painful(adjective, hard, difficult, complex) |
| problematic(adjective, hard, difficult, complex) |
| sensitive(adjective, hard, difficult, complex, subtle) |
| toilsome(adjective, hard, difficult, complex) |
| unbearable(adjective, hard, difficult, complex) |
| sad(adjective, hard, difficult, complex, greatness) |
| dire(adjective, hard, difficult, complex) |
| extreme(adjective, strong, hard, great, sharp) |
| labyrinthine(adjective, hard, difficult, complex) |
| leaden(adjective, hard, difficult, complex) |
| massive(adjective, hard, difficult, complex) |
| ponderous(adjective, hard, difficult, complex) |
| sheer(adjective, hard, difficult, complex) |
| thorough(adjective, complete, sensible, intense, full) |
| heavy(adjective, easy, severe, obscure, slang) |
| wise(adjective, sharp, bright, deep, intelligent) |