closed book
closed book noun: a person or thing that cannot be easily understood; someone or something incomprehensible or puzzling.
Noun
closed book (plural closed books)
- A person or thing that cannot be easily understood; someone or something incomprehensible or puzzling.
- Her courteous, sedate, inexorable husband, whose will she could not bend, whom she could not cajole, whose mind was a closed book to her — a book which had lain by her hand for three years, which she had never had the curiosity to open!1906, Mary Cholmondeley, Prisoners: Fast Bound in Misery and Iron
- Like the activities of British Railways Research Department, developing, testing and modifying diesel locomotives before their acceptance for service is another behind-the-scenes activity which is a closed book to most passengers and to many railwaymen.1962 April, R. K. Evans, “The Acceptance Testing of Diesel Locomotives”, in Modern Railways, page 266
Antonyms of closed book
Forms of closed book
| plural | closed books |
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Questions about closed book
- What does closed book mean?
- Closed book means a person or thing that cannot be easily understood; someone or something incomprehensible or puzzling.
- What part of speech is closed book?
- Closed book is a noun.
- What is the plural of closed book?
- The plural of closed book is closed books.
Words near closed book in the dictionary
Source and license
Adapted from Wiktionary: closed book (page history and authors). Text available under the Creative Commons Attribution-ShareAlike 4.0 license. Word.ws reformatted the entry and added links. Wiktionary data of 2026-09-02.
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Pronunciation audio from Wikimedia Commons, each file under its own free license: en-au-closed book.ogg.
Cite this entry: “closed book.” Word.ws, https://word.ws/closed_book. Based on Wiktionary, CC BY-SA 4.0.