いい年としして

expression

despite being old enough to know better; acting one's age

Used to criticize or express surprise at someone's immature or inappropriate behavior given their age. Often followed by a negative evaluation.

• いい年とししてそんなことで泣なくなよ。

  Don't cry over something like that at your age.

• いい年としして、まだ親おやに頼たよっている。

  Even though he's old enough to know better, he still depends on his parents.