hush up

hush up  {v.}
1. To keep news of (something) from getting out; prevent people from knowing about.
It isn't always easy to hush up a scandal.
2.  {informal}
To be or make quiet; stop talking, crying, or making some other noise. — Often used as a command.
"Hush up," Mother said, when we began to repeat ugly gossip.
Categories: informal verb