每日商務英語 第568期:祕密​的

hush-hush -------- 祕密的（形容詞，非正式）

英文釋義
(adjective, INFORMAL) Describing something done in secret.

例句
Several engineers in my company are working on some hush-hush project they never discuss with anyone.
我公司的幾位工程師正在搞一個極祕密的項目，從不和別人談論它。