Can I use “stop it” instead? Are "stop it" and "shut up" interchangeable?
Native speaker’s answer
Rebecca
Good question. This use of "shut up" should not be confused with the literal meaning, which is a rude way to tell someone to stop talking. Instead "shut up" is being used in its slang form, as an exclamation of amazement or excitement. As such it can't really be replaced by "stop it". Ex: Shut up! I got an A! Ex: A: He said you were cute. B: Shut up! He did?