Eng

Unknown...

秘

Clandestine, Classified, Confidential, Hidden, Mysterious, Secret, Unknown

默默無聞

Unknown

(In one's heart, Quietly, Silently, Wordlessly)

名不見經傳

Anonymous, Unknown

(Didn't see)

無名

Innominate, Nameless, Unknown

不明

Unexpected, Unknown

不得而知

Unknown

(Am not, Are not allowed, Cannot, Is not, Must, Not be, Was not, Were not)

不詳

Unknown

未知

Unidentified, Unknown, Unpredictable

未知的

Unknown

(Unidentified, Unpredictable)

未知數

Unknown

(Unidentified, Unpredictable)