| difficult(adjective, hard, difficult, complex) |
| severe(adjective, hard, difficult, complex, rigid) |
| unyielding(adjective, close, strong, hard, tough) |
| rough(adjective, hard, easy, severe, difficult) |
| tricky(adjective, hard, easy, difficult, complex) |
| trying(adjective, hard, difficult, complex, troublesome) |
| taut(adjective, order, close, strong, hard) |
| precarious(adjective, hard, difficult, complex, troublesome) |
| nasty(adjective, hard, difficult, complex) |
| proof(adjective, strain, firmness, labour, hardiness) |
| sticky(adjective, hard, easy, difficult, informal) |
| disturbing(adjective, hard, difficult, complex, troublesome) |
| laborious(adjective, hard, difficult, complex) |
| cheap(adjective, close, give, mean, informal) |
| penurious(adjective, close, give, mean, poor) |
| oppressive(adjective, hard, difficult, complex) |
| problematic(adjective, hard, difficult, complex) |
| resistant(adjective, strong, strain, firm, solid) |
| steadfast(adjective, strain, firmness, rigid, labour) |
| penny-pinching(adjective, close, give, mean, spare) |