senile

Relating to or having diminished cognitive function, as when memory is impaired, because of old age.

Being a disease or condition whose cause is primarily advanced age.

At the end of an erosion cycle.

In physical geography, exhibiting features of old age in the geographical cycle: said of worn-flown land-forms.

Of, pertaining to, or characteristic of old age; proceeding from age; especially, pertaining to or proceeding from the weaknesses that usually attend old age.