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closed books

noun

plural of closed book
as in mysteries
something hard to understand or explain the couple's unorthodox marriage is definitely a closed book to those outside of the relationship

Synonyms & Similar Words

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Example Sentences

Recent Examples of Synonyms for closed books
  1. mysteries
  2. puzzles
  3. secrets
Noun
  • Once there, Roman will study some of the biggest mysteries in astronomy, from dark energy to the formation of galaxies.
    — Thomas Fauchez, The Conversation, 14 Sep. 2026
  • Produced for Arte, the unscripted series, which is set in Paris, Rome, London and New York, sheds light on one of the art world’s greatest mysteries.
    — Ed Meza, Variety, 8 Sep. 2026
Definition of mysteries
Noun
  • In Puebla, authorities discovered 300 graphics processing units (GPUs), 80 medium-voltage terminals and eight ​satellite antennae — all geared to compete against millions of other machines to solve puzzles and create valuable new crypto coins.
    — CNN Money, CNN Money, 14 Sep. 2026
  • Though their origins may be shrouded in mystery, fast radio bursts (FRBs) could be used to probe some of the universe's biggest puzzles.
    — Robert Lea, Space.com, 10 Sep. 2026
Definition of puzzles
Noun
  • But, behind the scenes, King held deep secrets and struggled with her own identity.
    — Matthew Carey, Deadline, 17 Sep. 2026
  • This is a melodrama of malicious secrets and manipulative lies that may lead to divorce, desertion and even death.
    — Murtada Elfadl, Variety, 16 Sep. 2026
Definition of secrets
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.

Browse Nearby Words

closed book
closed books
closed-captioning
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Cite this Entry

“Closed books.” Merriam-Webster.com Thesaurus, Merriam-Webster, https://www.merriam-webster.com/thesaurus/closed%20books. Accessed 21 Sep. 2026.

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