So that's what the Government's so scared and hush-hush about.
This will be hush-hush for awhile, then left to dissolve of itself.
Mr. Atkins explained that naturally the affair was hush-hush.
It's all hush-hush so it won't leak out like the atom bomb did.
She was a "hush-hush" ship—one of the wonders of the Navy still.
Our Hush-hush Department seems to have grown very ...