senile

se·nile

adj \ˈsēn-ˌīl also ˈsen-\

Definition of SENILE

1

: of, relating to, exhibiting, or characteristic of old age <senile weakness>; especially : exhibiting a loss of mental faculties associated with old age

2

: being a cell that cannot undergo mitosis and is in the stage of declining functional capacities prior to the time of death <senile red blood cells>