Apparently there's a very hush-hush project under way up north.

貌似这里往北的地方有个非常机密的项目正在进行。

《柯林斯英汉双解大词典》

Hamilton says he failed tests, but managed to explain it away, or hush it up.

BBC: Lance Armstrong: Tyler Hamilton on 'how US Postal cheated'

Conservative Republicans have opted to keep their mouth shut during the election to help Bush win, but they won't hush up forever.

CNN: The Lover vs. the Fighter

Principals try to hush up crimes to avoid sullying the school's reputation.

ECONOMIST: South Africa: Wolves in teachers’ hats | The