To grow old; to age and become elderly.
祖父は最近目に見えて年老いてきた。
My grandfather has visibly grown older recently.
年老いると、健康管理にいっそう気を付ける必要がある。
As one grows old, it's necessary to pay more attention to health management.
彼女は年老いる両親の面倒を見ている。
She is taking care of her aging parents.