| problematic(adjective, hard, difficult, delicate, complex) |
| rugged(adjective, hard, difficulty, difficult, complex) |
| toilsome(adjective, hard, difficult, complex, awkward) |
| trying(adjective, hard, difficulty, difficult, complex) |
| burdensome(adjective, hard, difficult, complex, awkward) |
| composite(adjective, hard, difficult, complex) |
| oppressive(adjective, hard, difficult, complex, tedious) |
| rough(adjective, hard, difficult, complex, awkward) |
| severe(adjective, hard, difficult, complex, awkward) |
| sinuous(adjective, hard, difficult, complex) |
| sticky(adjective, hard, difficult, delicate, complex) |
| grinding(adjective, hard, difficult, complex, awkward) |
| involute(adjective, hard, simple, difficult, complex) |
| nasty(adjective, hard, evil, difficult, complex) |
| sensitive(adjective, hard, difficult, complex) |
| stressful(adjective, hard, difficult, complex) |
| tight(adjective, hard, difficult, complex) |
| ambitious(adjective, hard, difficult, complex) |
| anfractuous(adjective, hard, difficult, complex) |
| backbreaking(adjective, hard, difficult, complex, awkward) |