| refractory(tough, difficult, wild, awkward, obstinate) |
| resolute(tough, difficult, obstinate, stubborn, willful) |
| secretive(strange, unknown, curious, concealed, inexplicable) |
| self-willed(tough, difficult, wild, awkward, obstinate) |
| sphinxlike |
| spiritual(strange, unknown, curious, concealed, inexplicable) |
| strange |
| subjective(strange, unknown, curious, concealed, inexplicable) |
| symbolic(strange, unknown, curious, concealed, inexplicable) |
| tenacious(tough, difficult, wild, awkward, obstinate) |
| thorny |
| tough(difficult, awkward, obstinate, stubborn, willful) |
| transcendental(strange, unknown, curious, concealed, inexplicable) |
| unbending(tough, difficult, obstinate, stubborn, willful) |
| uncanny(adjective, strange, unknown, curious, concealed) |
| uncompromising(tough, difficult, obstinate, stubborn, willful) |
| unconcluded(adjective, unable, answered) |
| uncooperative(tough, difficult, wild, awkward, obstinate) |
| undefeatable |
| undisciplined(tough, difficult, wild, awkward, obstinate) |