| tight(adjective, hard, difficult, complex, troublesome) |
| complicated(adjective, hard, difficult, complex, awkward) |
| knotty(adjective, hard, severe, rough, difficult) |
| tricky(adjective, hard, difficult, complex, awkward) |
| dire(adjective, hard, difficult, complex, painful) |
| thorny(adjective, hard, difficult, complex, demanding) |
| serious(adjective, hard, tough, easy, difficult) |
| sheer(adjective, hard, sharp, difficult, complex) |
| grinding(adjective, hard, difficult, harsh, cruel) |
| exhausting(adjective, dull, hard, tough, difficult) |
| onerous(adjective, dull, hard, great, tough) |
| unbearable(adjective, hard, difficult, complex, painful) |
| ambitious(adjective, hard, ability, difficult, complex) |
| weighty(adjective, hard, difficult, heavy, complex) |
| cruel(adjective, hard, difficult, complex, painful) |
| hefty(adjective, dull, hard, difficult, harsh) |
| intricate(adjective, hard, difficult, complex, awkward) |
| sensitive(adjective, hard, difficult, complex, painful) |
| Gordian(adjective, hard, difficult, complex, intricate) |
| byzantine(adjective, hard, difficult, complex, intricate) |