Medical 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>
Seen and Heard
What made you want to look up senile? Please tell us where you read or heard it (including the quote, if possible).