| industry(noun, activity, care, vigor, intensity) |
| assiduity(noun, activity, care, vigor, intensity) |
| difficulty(noun, situation, problem, adversity, toughness) |
| diligence(noun, activity, care, application, perseverance) |
| operoseness(noun, difficulty, strenuousness) |
| application(noun, activity, care, vigor, intensity) |
| labor(noun, activity, trouble, difficulty, pain) |
| labour |
| sweat |
| toughness(noun, difficulty, hardness) |
| arduousness(noun, trouble, difficulty, pain, struggle) |
| assiduousness(noun, activity, care, vigor, intensity) |
| complexity(noun, adversity, complication, intricacy, complicatedness) |
| complication(noun, trouble, difficulty, pain, struggle) |
| drudgery(noun, activity) |
| hardness(noun, difficulty, toughness) |
| industriousness(noun, activity, care, application, industry) |
| intricacy(noun, adversity, complication, complexity, complicatedness) |
| painfulness(noun, trouble, difficulty, pain, struggle) |
| strain(noun, trouble, difficulty, pain, struggle) |