Hush up

Hush up now; you have talked too much.

Some people say he knew too much and they killed him to hush him up.

They hushed up the suicide to prevent bad publicity.

As he took John Willet's view of the matter in regard to the propriety of not bruiting the tale abroad, unless the spirit should appear to him again, in which case it would be necessary to take immediate counsel with the clergyman, it was solemnly resolved that it should be hushed up and kept quiet.