closed book


closed book


  • something that one knows or understands nothing about.
  • a topic or somebody one is completely ignorant of.
  • anything that you acknowledge has entirely ended.
  • something or someone that is difficult to understand.
  • a puzzle or a mystery.

Examples in a Sentence

  1. I love reading and learning. But physics is a closed book to me.
  2. Chris does not love history. So, he knows nothing about Buddha. To him, his life is a closed book.
  3. Although the investigators tried to interrogate Daniel for the mysterious murder of his wife, he remained dumb and indecipherable as a closed book.
  4. I am scared that this mathematical formula will be a closed book to Miriam.
  5. Even to us, her best friend, Margret, is always something of a closed book.
  6. I’m afraid that this new physics equation will always be a closed book to me.
  7. Although I love reading novels, there is one such novel that I like to read, which is The Closed Book of Sarah’s Soul.


A closed book was used in the early 1900s when one could not access information in a book as it was closed. But in recent years, the meaning has changed to allude to someone or something you don’t know about or understand. It’s used to describe a mystery, a secret, or a person who doesn’t want to be discussed or asked about.

The idiom was first recorded in 1910–15, and words used in association with this saying include close communion, close corporation, close cropped, close captioned, etc. Some words related to this expression are secrecy, puzzlement, complexity, enigma, drama, and riddle, among others.

Share your opinions

What's on your mind?