The full form of BBO is bad bitches only.
The most widely accepted meaning of the acronym “BBO” according to the Urban Dictionary is that the acronym stands for the phrase “bad bitches only.”

Origin of BBO
There is no definitive information regarding the origin of the acronym “BBO.” However, in the context mentioned above the earliest entry made by users in the Urban Dictionary was 2011, an indication that the phrase is at least eight years old.

Other Meanings
The acronym “BBO” can have multiple meanings that aren’t as widely accepted. A user in 2009 posted in the Urban Dictionary that the phrase represented by this acronym was “bitch back off.” Another user in 2008 said the acronym stood for “beyond body odor” which came from a popular Seinfeld episode. Another user stated that the acronym represented the phrase “being bored online” in 2010. To determine the meaning implied, one is forced to look at the context that the acronym is being used to convey.

Example Conversations
Friend 1: Have you thought any more about asking Brian to the dance on Friday?
Friend 2: I have given it some thought and I think I am just going to go by myself.
Friend 1: Well, you won’t be by yourself. I am going to go with you. Why aren’t you going to ask Brian?
Friend 2: I don’t think I am the right fit for him. He seems to like BBO. I am not his type.