막아야

must block, have to stop

→ 막다
verb · informal Rare #22,814
must block, have to stop This is a form of 막다 used before another verb or ending to express that someone must or should block or stop something.
KO: 공이 골대에 들어가지 않게 막아야 해요.
EN: You have to block the ball so it doesn't go into the goal.
Conjugation of 막다
Necessitative
막아야

그래서 그걸 막아야 할 의무가 있다고 생각하신 거 고요?

So you felt you had a duty to stop it?

— 콘클라베 (2024)

잘 막아야 할 텐데

I hope they can block it properly.

— RRR: 라이즈 로어 리볼트 (2022)

야, 야, 제대로 좀 막아야, 인마!

Hey, hey, block it properly, man!

— I Saw the Devil (2010)