건지 모르겠어

I don't know what ... is

→ 것+인지

phrase Rare #17,063

I don't know what ... is 건지 introduces an indirect question; translate it according to the question word before it, such as what, who, or how.

KO: 이게 왜 필요한 건지 모르겠어.

EN: I don't know why this is necessary.