confidential

形容词 confidential:

1. entrusted with private information and the confidence of another
2. (of information) given in confidence or in secret
   同义词：secret
3. denoting confidence or intimacy
4. the level of official classification for documents next above restricted and below secret; available only to persons authorized to see documents so classified

1. A doctor who gives away confidential information about patients is not behaving professionally.
   医生把病人的私人资料透露出来是违反职业道德的。
2. Don't repeat what I said (to anyone) it's confidential.
   别把我的话告诉别人--这是秘密。
3. I must stress that what I say is confidential.
   我要强调我说的话是保密的。
4. He has been on confidential missions to Berlin.
   他前往柏林执行秘密任务。
5. Don't be too confidential with strangers.
   不要过份相信陌生人。
6. He told me the confidential information.
   他向我透露了这个秘密的信息。

con.fi.den.tial

adj.Abbr. conf.（形容词）缩写 conf.
Done or communicated in confidence; secret.
秘密的：秘密地进行或交流的；秘密的
Entrusted with the confidence of another:
可信任的：对另一个人寄以信任的：
例句：
a confidential secretary.
机要秘书

Denoting confidence or intimacy:
亲密的：表示信任或亲密的：
例句：
a confidential tone of voice.See Synonyms at familiar
亲密的声调参见 familiar

Containing secret information, the unauthorized disclosure of which poses a threat to national security.
机密的：包含机密信息的，未经授权泄露可能会危及到国家的安全的

【引伸】
con.fiden.tial.ity
con.fiden.tially
adv.（副词）