The abbreviation “ONB” stands for “Old News Bro.” The response is usually a snarky one. Where one person is trying to tell the other person that they are behind.
For example, “Yeah, I’ve already heard about that! ONB!” This type of sarcastic response might be considered rude to some
Intention: A person might say this if they are trying to reply to the other person and say that something they are being told to them is something that they already know.
“Oh yeah, I heard about this already… ONB!”
Emotion: Emotive
Intention: A person would say “ONB” when they are trying to be emotive about the subject matter. And allude to the other person that they are behind on something they are discussing.