anonymity

Every step will be taken to preserve your anonymity..将采取各种措施确保你的姓名保密。

One official, who spoke on condition of anonymity (= he would only speak if his name was not told ) , said the White House took the threat very seriously..一位不愿公开姓名的官员称，白宫非常重视这一威胁。

the anonymity of city streets (= you do not know anyone, and no one knows you ).城市街头人人互不相识

on condition of anonymity,在匿名的情况下