| obstinacy(noun, determination, resolution, firmness, steadfastness) |
| resolution(noun, strong, spirit, certain, determination) |
| rigorousness(noun, easy, difficulty, condition, discipline) |
| robustness(noun, health, force, body, power) |
| roughness(noun, power, difficulty, violence) |
| sternness(noun, easy, condition, discipline, firmness) |
| strictness(noun, easy, condition, discipline, firmness) |
| stringency(noun, easy, condition, discipline, firmness) |
| vigor(noun, health, force, body, power) |
| viscidity(noun, tenacity) |
| vitality(noun, health, force, body, power) |
| resoluteness(noun, support, control, strong, strength) |
| austerity(noun, easy, condition, discipline, firmness) |
| body(noun, health, state, force, quality) |
| bravery(noun, spirit, determination, resolution, courage) |
| bullheadedness(noun, resolution, tenacity) |
| buoyancy(noun, hard, power, strength, spirit) |
| chutzpah |
| complication(noun, difficulty, hardness) |
| dauntlessness(noun, resolution, courage, boldness) |