| tortuous(adjective, obscure, difficult, complex, sophisticated) |
| ticklish(adjective, hard, tough, difficult, delicate) |
| gnarly |
| problematical(adjective, hard, difficult, delicate, loose) |
| troublesome(adjective, hard, fancy, difficult, complex) |
| formidable(adjective, hard, severe, rough, difficult) |
| snarled |
| twisted |
| abstruse(adjective, hard, fancy, evil, obscure) |
| delicate(hard, difficult, complex, awkward, tricky) |
| knobbed |
| scabrous(adjective, rough, difficult, harsh, coarse) |
| awkward(adjective, tough, difficulty, difficult, delicate) |
| critical(delicate, awkward, complicated) |
| demanding(adjective, hard, tough, severe, rough) |
| enigmatic(adjective, hard, evil, obscure, difficult) |
| hairy(adjective, severe, rough, difficult, harsh) |
| knobby(adjective, harsh, coarse, irregular, uneven) |
| mystifying(adjective, hard, evil, delicate, loose) |
| prickly(thorny, spiky, spiny) |