| Achilles' heel |
| appetite(noun, weakness, informal, fault, failing) |
| bad habit(expression, weakness, fault, shortcoming) |
| catch(noun, weakness, crack, fault, failing) |
| crack(noun, weakness, fault, blemish, flaw) |
| enervation(noun, difficulty, weakness, fault, failing) |
| faintness(noun, difficulty, weakness, fault, failing) |
| fragility(noun, difficulty, weakness, fault, failing) |
| hole(noun, weakness, crack, fault, blemish) |
| impairment(noun, difficulty, weakness, fault, failing) |
| inconstancy(noun, difficulty, weakness, fault, failing) |
| indecision(noun, difficulty, weakness, fault, failing) |
| invalidity(noun, difficulty, weakness, fault, failing) |
| irresolution(noun, difficulty, weakness, fault, failing) |
| languor(noun, difficulty, weakness, fault, failing) |
| liability |
| problem(noun, trouble, difficulty, weakness, bar) |
| prostration(noun, difficulty, weakness, fault, failing) |
| rift(noun, weakness, crack, fault, blemish) |
| senility(noun, difficulty, weakness, fault, failing) |