If old people become ~, they become confused, can no longer remember things, and are unable to look after themselves.
ADJ
senility
The old man was showing unmistakable signs of senility.
N-UNCOUNT
If old people become ~, they become confused, can no longer remember things, and are unable to look after themselves.
ADJ
senility
The old man was showing unmistakable signs of senility.
N-UNCOUNT
Collins COBUILD. Толковый словарь английского языка для изучающих язык Коллинз COBUILD (международная база данных языков Бирмингемского университета) . 2012