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
  • Known as Kelvin-Helmholtz instability, or KHI, the swirling patterns could explain enduring solar mysteries, such as why the sun’s corona, or outer atmosphere, is much hotter than its surface.
    — Ashley Strickland, CNN Money, 5 Aug. 2026
  • That's the age of the lead character of Lee's seventh novel; Jeon-Gi is a fumbling initiate into the bewildering mysteries of preadolescence.
    — Colin Dwyer, NPR, 4 Aug. 2026
Definition of mysteries
Noun
  • Previous studies also have found differences between passive sedentary behaviors, such as television watching, and more mentally active ones, including solving puzzles and being mentally engaged during work.
    — Katia Hetter, CNN Money, 8 Aug. 2026
  • His passions lie in using AI to solve scientific puzzles, like curing diseases and discovering new materials, and in ensuring that AI doesn’t accidentally cause catastrophic harm to humanity.
    — Reed Albergotti, semafor.com, 5 Aug. 2026
Definition of puzzles
Noun
  • Decades later, her daughter Clara must confront the lingering impact of her family’s scandal and the secrets that have shaped her own life.
    — Kait Hanson, Southern Living, 7 Aug. 2026
  • Remediate exposed secrets continuously Improve hygiene before the breach.
    — Eric Fourrier, Forbes.com, 6 Aug. 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 9 Aug. 2026.

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