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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Although these practical applications are still on the horizon, the study highlights how physics can explore the natural world to solve long-standing mysteries.—
Mrigakshi Dixit,
Interesting Engineering,
4 May 2026 -
The Hallmark Channel series is traveling back to 1920s Port Haven during its upcoming fourth and final season, as mysteries are unearthed and lingering questions about the past find a way to haunt the present-day Landry clan.—
Alex Gurley,
PEOPLE,
3 May 2026
Noun
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Check out the all new PLAY hub with puzzles, games and more!—
Brendan Morrow,
USA Today,
7 May 2026
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Apple works at this vertiginous juncture where Emily Dickinson goes rumbling into Etta James and, lately, Beyoncé; where Nico solves puzzles with Randy Newman, Kurt Weill, Nina Simone and the Beatles.—
New York Times,
New York Times,
28 Apr. 2026
Noun
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The people running the computers won’t release their secrets about how teams are really ranked.—
Eric Sondheimer,
Los Angeles Times,
9 May 2026
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Years later, the teenaged Daughter lets in a woman from the outside, which causes chaos in their relationship and reveals some unpleasant secrets.—
K. Thor Jensen,
PC Magazine,
8 May 2026
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Cite this Entry
“Closed books.” Merriam-Webster.com Thesaurus, Merriam-Webster, https://www.merriam-webster.com/thesaurus/closed%20books. Accessed 10 May. 2026.
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