| Gordian(adjective, hard, difficult, complex, intricate) |
| ambitious(adjective, hard, difficult, complex) |
| arduous(adjective, hard, tough, difficult, complex) |
| burdensome(adjective, hard, difficult, complex) |
| disturbing(adjective, hard, difficult, complex) |
| elaborate(adjective, hard, difficult, complex, intricate) |
| impossible(adjective, hard, difficult, complex) |
| knotted(adjective, hard, difficult, complex) |
| laborious(adjective, hard, difficult, complex) |
| nasty(adjective, hard, difficult, complex) |
| operose(adjective, hard, difficult, complex) |
| profound(adjective, hard, difficult, complex) |
| sophisticated(adjective, hard, difficult, complex, intricate) |
| toilsome(adjective, hard, difficult, complex) |
| doubtful(adjective, clear, open, rough, delicate) |
| far out(adjective, hard, difficult, complex) |
| perplexed(adjective, hard, difficult, complex) |
| severe(adjective, hard, difficult, complex) |
| troubled(adjective, hard, difficult, complex) |
| questionable(adjective, clear, open, rough, certain) |