Best of Regina George https://www.youtube.com/watch?v=Y_dCc-9pEPM
Here are quotes from the movie "Mean Girls".
Regina: Wait. Sit down. Seriously, sit down. Why don't I know you?
Cady: I'm new. I just moved here from Africa.
Cady: I used to be home-schooled.
Regina: Wait. What?
Cady: My mom taught me at home...
Regina: No, no. I know what home-school is. I'm not retarded. So you've actually never been to a real school before? Shut up. Shut up.
Cady: I didn't say anything.
What does Regina mean by "Shut up"? Thanks in advance.