A male who plays the sport of lacrosse and for some reason thinks that this automatically makes him the "chillest" guy ever. Lax bros tend to wear $2 lacrosse pennies that they got from a summer camp in public. Lax bros will never fail to overreact to anything they hear that may resemble a threat or challenge. Lax bros commonly don't attempt any education for they think they will get into a Division 1 university just for playing lacrosse. Lax bros tend to be dochebags to anyone who is not among them, and learn about 70% of their vocabulary from the MTV show Jersey Shore And lastly, they will systematically rip on any other sport simply because they have fixated themselves so much on lacrosse that any other sport is considered "gay" to them.
Normal lacrosse player: Why are you wearing a lacrosse penny?
Lax bro: You talkin' to me bitch? You wanna fight?
Normal lacrosse player: What?