| repugnant(adjective, reverse, unfriendly, antagonistic, contrary) |
| restive(adjective, negative, hostile, different, adverse) |
| retrograde(adjective, reverse, antagonistic, contrary, adverse) |
| reverse(adjective, negative, hostile, antagonistic, contrary) |
| reversed(adjective, reverse, antagonistic, contrary, adverse) |
| ruled-out |
| separate |
| silly(adjective, absurd) |
| stupid(adjective, absurd) |
| subtle(adjective, hard, delicate, complex, tricky) |
| tangled(adjective, hard, obscure, sophisticated, tricky) |
| thorny(adjective, hard, delicate, complex, tricky) |
| ticklish(adjective, hard, delicate, complex, tricky) |
| unalike(adjective, reverse, antagonistic, contrary, adverse) |
| uncertain(adjective, doubtful, vague, dubious, ambiguous) |
| uncomplimentary(adjective, keen, sharp, like, dry) |
| unconnected(adjective, reverse, antagonistic, contrary, adverse) |
| unexplainable |
| unfathomable(adjective, hard, obscure, sophisticated, tricky) |
| unimaginable |