closed book

noun

1. something that is not known or cannot be understood; a mystery or puzzle:

   Abstract art is a closed book as far as I'm concerned.

closed book

noun

1. something deemed unknown or incapable of being understood
2. a matter that has been finally concluded and admits of no further consideration

Word History and Origins

Origin of closed book¹

First recorded in 1910–15

Example Sentences

The girl sat with closed book, looking at his face as he slept.

From Project Gutenberg

I love novels, but there is no wonderful novel which I so much should like to read as the closed book which is your soul.

From Project Gutenberg

He does not read, and so knows nothing of the inspiration of literature, and the past is to him a closed book.

From Project Gutenberg

Although Valentine and his two comrades might interrogate the desert, it remained dumb and indecipherable as a closed book.

From Project Gutenberg

Her face turned deadly pale, and she clenched the closed book in her pallid hands.

From Project Gutenberg

Related Words

• conundrum
• enigma
• problem
• question
• riddle
• secrecy
• subtlety
• thriller