On Jah Bro is used mainly by young men the term "on jah comes from the rapper xxxtentacion witch his real nah is Jahseh. When saying on jah it means you are very serious because you are swearing on a dead person's life

A cultural and aesthetic mind-state that prioritizes making money, even as an “underground” or “radical” creator. The work isn’t made for money, but it’s the money that matters the most.