| rigor(noun, severity, harshness, strictness, obstinacy) |
| rigorism |
| safeguard(support, fight, opposition, resistance, fighting) |
| screen(support, fight, opposition, resistance, fighting) |
| shield(support, fight, opposition, resistance, fighting) |
| spunk(noun, resolve, determination, firmness, persistence) |
| stand(support, fight, opposition, resistance, fighting) |
| starch(noun, resolve, determination, firmness, persistence) |
| staunchness(noun, resolve, determination, firmness, persistence) |
| steadfastness(noun, resolve, determination, firmness, persistence) |
| steeliness |
| stick-to-itiveness(noun, resolve, determination, firmness, persistence) |
| stiff temper |
| stomach(noun, resolve, determination, firmness, persistence) |
| strength of purpose(noun, expression, idiom, resolve, determination) |
| striking back(expression, support, fight, opposition, resistance) |
| strong-mindedness(noun, implacability) |
| struggle(support, fight, opposition, resistance, fighting) |
| support(fight, opposition, resistance, fighting, impermeability) |
| tenaciousness(noun, resolve, determination, firmness, obstinacy) |