| anfractuous(adjective, hard, difficult, complex) |
| backbreaking(adjective, hard, difficult, complex, awkward) |
| composite(adjective, hard, difficult, complex) |
| compound(adjective, hard, difficult, complex) |
| esoteric(adjective, hard, evil, difficult, complex) |
| hard to understand(expression, adjective, idiom, hard, difficult) |
| lumpish(adjective, hard, difficult, complex, density) |
| massive(adjective, hard, difficult, complex, density) |
| perplexed(adjective, hard, difficult, complex) |
| serious(adjective, hard, difficult, complex, awkward) |
| toilful(adjective, hard, difficult, complex, awkward) |
| messy(adjective, hard, difficult, complex) |
| precarious(adjective, hard, difficult, complex) |
| stubborn(adjective, hard, difficulty, difficult, complex) |
| tangled(adjective, hard, simple, obscure, difficulty) |
| baffling(adjective, hard, tough, difficult, awkward) |
| convoluted(adjective, hard, simple, fancy, obscure) |
| perplexing(adjective, hard, fancy, obscure, difficult) |
| gnarled(adjective, density) |
| puzzling(adjective, hard, fancy, evil, obscure) |