싸우는 건

fighting

→ 싸우다
phrase Rare #24,696
fighting 건 is a shortened form of 것은, making the action the topic. Depending on context, it can also mean “as for fighting.”
KO: 싸우는 건 싫어요.
EN: I don't like fighting.

싸우는 건 안 돼요

No fighting.

— 붉은 돼지 (1992)

싸우는 건 그만할래요

I want to stop fighting.

— 빈폴 (2019)