年とし寄よりの冷ひや水みず

expression, noun

an old person's reckless act; old people doing dangerous things

An idiomatic admonishment used when an elderly person does something risky or inappropriate for their age, often implying they should know better.

• 祖そ父ふが真ま冬ふゆに薄うす着ぎで外そとに出でようとしたので、「年とし寄よりの冷ひや水みずだよ」と注ちゅう意いした。

  When my grandfather tried to go outside lightly dressed in midwinter, I warned him, 'That's an old person's reckless act.'

• 八はち十じゅっ歳さいでスカイダイビングに挑ちょう戦せんするなんて、年とし寄よりの冷ひや水みずと言いわれても仕し方かたない。

  Trying skydiving at eighty—it's no wonder people call it an old person's indiscretion.