짓이에요

it's someone's doing

→ 짓
phrase Uncommon #12,541
it's someone's doing 짓 means an act or deed, often with a negative or disapproving nuance. 이에요 is the polite form of “is.”
KO: 그건 네 짓이에요.
EN: That's your doing.

그건 비겁한 짓 이에요

That's cowardly.

— 요짐보 (1961)

놈들의 짓 이에요

Those bastards are behind it.

— 황야의 무법자 (1964)

여자애 짓 이에요

It's something a girl would do.

— 문라이즈 킹덤 (2012)

미친 짓 이에요, 허락 못 해요

That’s crazy. I can’t allow it.

— 잉글리쉬 페이션트 (1996)

그의 짓 이에요

It was his doing.

— 반지의 제왕: 왕의 귀환 (2003)