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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
  • The new show Sterling Point features a mysterious inheritance, a teen love triangle and deep generational lies and secrets.
    — Brittney Melton, NPR, 4 Sep. 2026
  • Her arrival stirs enough secrets, crushes, and shifting loyalties to fill an eight-episode TV show.
    — Rhoda Feng, New Yorker, 4 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 18 Sep. 2026.

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