noun
infirmity
in-FUR-muh-tee/ɪnˈfɜːrməti/
Weakness or ill health of the body or mind.
Despite his infirmity, he still enjoys a short daily walk.

Etymology
Infirmity names the state of being “not strong.” The underlying lack of strength applies to bodily frailty and also to mental or moral weakness, rather than only to a particular disease.
In context
infirmity of the body weakness that he's unable to even move or obviously unable to perform the function
More examples
- The infirmities of old age make everyday tasks more difficult.
- Her growing infirmity means she needs help getting dressed.
- The evaluation looks for signs of physical or mental infirmity.
Forms
infirmity · infirmities
infirm adjective — Physically weak or in poor health.