break, beat up, annoy, piss off
Tu lui casses la gueule, ou c'est moi qui le fais ?
Are you going to beat him up, or should I do it?
— 3 Idiots (2009)
Je te casse le bras et tu me casses les jambes.
I break your arm, and you break my legs.
— Ne Zha 2 (2025)
Tu casses l'ambiance avec tes remarques.
You're ruining the atmosphere with your remarks.