What does "pop off" mean? Is it a British expression?

Native speaker’s answer
Rebecca
It actually has a few meanings! And that's right. It is a British expression! It means to go out somewhere quickly or suddenly. "pop off" can also mean to speak for a long time when angry, rather spontaneously. Or, "pop off" can also mean to die. Ex: I had to pop off to the pet store to get some more dog food. Ex: My lecturer just popped off in class today. Maybe he was having a bad day. Ex: When I pop off, I want you to have my piano.