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
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Easily recognizable by her orange turtleneck and thick-rimmed glasses, Velma is known for her quick wit, keen eye for detail and ability to solve even the trickiest mysteries.—
Samantha Stutsman,
PEOPLE,
14 June 2026 -
Neurological mysteries, immaculate conception, exposure therapy, a natural-birth cult (cults!—
Sara Holdren,
Vulture,
14 June 2026
Noun
-
Check out the all new PLAY hub with puzzles, games and more!—
Daryl Austin,
USA Today,
18 June 2026
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To test that, the final group completed cognitively demanding games such as mazes and shape puzzles called tangrams that contained no academic content.—
Supreet Kaur,
Scientific American,
10 June 2026
Noun
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In that series, Nikulov becomes the director of Roscosmos and develops a relationship with Margo Madison (Wrenn Schmidt) during the Apollo-Soyuz program that leads to costly secrets shared and a very bad outcome.—
Jeff Spry,
Space.com,
19 June 2026
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As the funeral unfolds, however, the village’s dark secrets slowly emerge.—
John Hopewell,
Variety,
19 June 2026
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“Closed books.” Merriam-Webster.com Thesaurus, Merriam-Webster, https://www.merriam-webster.com/thesaurus/closed%20books. Accessed 22 Jun. 2026.
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