It's a word for someone you like. Hey, boo, how are you doing? It's like beau in French. You can also say sweetie or honey.

Do you have more context? The one I know is not slang - it's a word you say (loudly) to frighten people.

It means 'girlfriend' or 'boyfriend.' But not really someone you've just met, someone you care about a lot. You hear it a lot in R and B songs.