| trickiness(noun, difficulty, adversity, complication, complexity) |
| vigor(noun, control, force, power, strength) |
| wearying(noun, difficulty) |
| adequacy(noun, force, power, strength, ability) |
| application |
| ardor |
| ardour |
| arm(noun, control, force, power, strength) |
| authority(noun, control, force, power, strength) |
| awkwardness(noun, trouble, difficulty, pain, struggle) |
| barricade(noun, trouble, difficulty, pain, struggle) |
| cantankerousness(noun, difficulty) |
| capability(noun, force, power, strength, ability) |
| capacity(noun, force, power, strength, ability) |
| check(noun, trouble, difficulty, pain, struggle) |
| clout(noun, control, force, power, strength) |
| command(noun, control, force, power, strength) |
| competence(noun, force, power, strength, ability) |
| concentration |
| contrariness(noun, difficulty) |