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
Noun
-
In truth, the mysteries and compromises of mapping New York are evident every day.—
Adam Gopnik,
New Yorker,
4 Jan. 2026 -
The gang was younger, the mysteries were smaller, and everything felt lighter.—
Alex Shoemaker,
Parents,
4 Jan. 2026
Noun
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Then imagine there are a couple of hundred other people with very similar puzzles, also looking for particular pieces to fit their own jigsaw.—
Idaho Statesman,
Idaho Statesman,
7 Nov. 2025
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Check out the all new PLAY hub with puzzles, games and more!—
Kaycee Sloan,
Cincinnati Enquirer,
7 Nov. 2025
Noun
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Later that decade, alarm bells started going off within the CIA and FBI over the arrest and execution of numerous double agents feeding secrets to the United States.—
Josh Campbell,
CNN Money,
7 Jan. 2026
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But what begins as a dream job quickly unravels into something far more dangerous — a sexy, seductive game of secrets, scandal, and power.—
Matt Grobar,
Deadline,
6 Jan. 2026
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“Closed books.” Merriam-Webster.com Thesaurus, Merriam-Webster, https://www.merriam-webster.com/thesaurus/closed%20books. Accessed 10 Jan. 2026.
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