hush-hush

(adjective) very secret, confidential

Example Sentences:

I want you to keep this hush-hush, but my wife is pregnant!

Our boss told us that our company had been bought by another, but he asked us to keep it very hush-hush.

Media:

Similar idioms:

1. bring something out into the open
2. lay something to rest
3. let the cat out of the bag
4. spill the beans
5. kill two birds with one stone