| fever(noun, disorder, disease, illness, defect) |
| fragileness(noun, strong, weakness, condition, failing) |
| ill health(noun, expression, disorder, weakness, fault) |
| indisposition(noun, disorder, disease, weakness, condition) |
| infection(noun, disorder, disease, illness, sickness) |
| instability(noun, weakness, fault, lack, lapse) |
| oldness |
| softness(noun, feebleness) |
| syndrome(noun, disorder, disease, illness, sickness) |
| virus(noun, disorder, disease, illness, sickness) |
| wasting(decline, ruin, collapse, failing, deterioration) |
| Achilles heel(noun, expression, weakness, fault, lack) |
| abatement(noun, drop, fall, failure, deterioration) |
| adulteration(decline, collapse, deterioration, impairment, degeneration) |
| affliction(noun, disorder, weakness, fault, illness) |
| ageing |
| aging |
| ague(noun, disease) |
| ailing(noun, disorder, weakness, fault, illness) |
| apoplexy(noun, disease) |