What's "bum" mean? Is it a slang?

Rebecca

Yes, "bum" is slang! It means a vagrant. It has a few other meanings, such as someone who's dedicated to one thing, or it could also refer to someone's butt in a mild way. Ex: You're going to become a bum if you don't get a job. Ex: He's such a beach bum. He's always surfing whenever he can. Ex: My bum is sore from sitting all day.