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
Relevance
Example Sentences
Recent Examples of Synonyms for closed books
Noun
-
New York — One of the biggest mysteries of the global economy is why the oil market has remained so calm during one of the greatest supply shocks in history.—
Matt Egan,
CNN Money,
9 June 2026 -
Solving the mysteries of Lewis’s art hasn’t been easy.—
Zachary Fine,
New Yorker,
8 June 2026
Noun
-
Check out the all new PLAY hub with puzzles, games and more!—
Liza Esquibias,
USA Today,
10 June 2026
-
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
-
The epic journey of Altar Stone To uncover the secrets of the Altar Stone, researchers combined sandstone provenance analysis—also known as mineral grain dating—with ice flow modeling to identify potential sources and transport pathways.—
Maria Mocerino,
Interesting Engineering,
6 June 2026
-
Mamie Van Doren isn’t done spilling secrets.—
Stephanie Nolasco,
FOXNews.com,
6 June 2026
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.
Cite this Entry
“Closed books.” Merriam-Webster.com Thesaurus, Merriam-Webster, https://www.merriam-webster.com/thesaurus/closed%20books. Accessed 13 Jun. 2026.
Copy CitationLove words? Need even more definitions?
Merriam-Webster unabridged
