The condition of being senile, especially the decline in mental faculties associated with old age. His family noticed signs of senility when he began forgetting familiar names and places.
A foolish remark, action, or trait regarded as typical of old age; an instance of senile behaviour. She dismissed his sudden outburst as just another of his senilities.
The state or fact of being old; advanced age (sometimes without implication of mental decline). Few in the medieval village lived long enough to reach senility.