나이 (가) The part “가” may be omitted. 아깝다

English rendering Act beneath one’s age or die too young Literal translation: “One’s age is a pity”

Meaning 1

하는 짓이나 말이 그 나이에 어울리지 아니하게 유치하다.

Act or speak childishly in a manner inappropriate to one’s age

Dictionary example 1

그것도 모르다니 나이가 아깝다 .

Not knowing even that is a disgrace at your age.

Meaning 2

Be regrettable because someone died early or suffered misfortune

Dictionary example 1

새파랗게 젊은 사람이 죽다니 나이가 아깝다 .

Such a young person dying—what a waste of those years.