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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
  • Nature, loss, and longing inspire these quiet verses, which conjure a sense of the immense mysteries governing the observable world.
    — The New Yorker, New Yorker, 21 Sep. 2026
  • All this time later, the horse was never found, no one's been arrested, and one of sport's great unsolved mysteries has never moved beyond cold case status.
    — Jon Wertheim, CBS News, 20 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 24 Sep. 2026.

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