Something that is hush-hush is secret and not to be discussed with other people. ( INFORMAL )
Apparently there’s a very hush-hush project under way up north...
= secret
ADJ
Something that is hush-hush is secret and not to be discussed with other people. ( INFORMAL )
Apparently there’s a very hush-hush project under way up north...
= secret
ADJ
Collins COBUILD Advanced Learner's English Dictionary. Английский словарь Коллинз COBUILD для изучающих язык на продвинутом уровне. 2006