nah broh - you're saying no, but you're doing it with the confidence of

you're saying no, but you're doing it with the confidence of a man who just won a bet

Nah broh, I'm not doing that. I just won ten bucks from you.

Nah broh, I ain't going to the store. I got my own money.

Nah broh, I'm not helping you fight. I just got a new pair of shoes.