| complex(adjective, hard, simple, difficult, delicate) |
| intricate(adjective, hard, simple, evil, difficulty) |
| complicated(adjective, hard, simple, evil, difficulty) |
| difficult(adjective, hard, rough, difficult, delicate) |
| involved(adjective, hard, simple, difficult, delicate) |
| thorny(adjective, hard, difficulty, difficult, delicate) |
| tough(adjective, hard, difficult, complex, troublesome) |
| hard(adjective, severe, rough, difficult, violent) |
| knotted(adjective, hard, difficulty, difficult, complex) |
| labyrinthine(adjective, hard, simple, difficulty, difficult) |
| Byzantine(adjective, hard, simple, difficult, complex) |
| tricky(adjective, hard, difficult, delicate, complex) |
| elaborate(adjective, hard, simple, difficult, complex) |
| rugged(adjective, hard, severe, difficulty, difficult) |
| sticky(adjective, hard, difficult, delicate, informal) |
| problematic(adjective, hard, difficult, delicate, complex) |
| rough(adjective, hard, difficult, complex, coarse) |
| arduous(adjective, hard, severe, rough, difficult) |
| sophisticated(adjective, hard, difficult, complex, involved) |
| daedal(adjective, hard, simple, difficult, complex) |