open book
noun1
Idiomatic Something whose salient aspects are obvious or easily interpreted.
- There is one, with a dark and thoughtful eye, Who is to all others a mystery; But his soul is to me an open book, And I read his mood in his slightest look; ...1860, Abby Maria Hemenway, “The Priest and The Maiden”, in Poets and Poetry of Vermont:
- This is the secret of Hegel, and the key to his hieroglyphics, and, if consistently used to interpret the sayings of his logic, it becomes an open book.1898, John Wesley Powell, Truth and Error or the Science of Intellection:
2 more examples
- On the surface of the ground or through the swaying branches of the trees the spoor of man or beast was an open book to the ape-man, but even his acute senses were baffled by the spoorless trail of the airship.1921, Edgar Rice Burroughs, Tarzan the Untamed:
- 2009, May 21, Barack Obama, speech, Protecting Our Security and Our Values But I have never argued – and never will – that our most sensitive national security matters should be an open book.
2
Idiomatic A person who responds candidly to questions or openly displays their emotions or intentions.
- He is an open book. Everyone can see that he removes nothing, conceals nothing, reserves nothing for himself.1986, Adrienne von Speyr, Hans Urs von Balthasar, The Christian State of Life:
- Chapter 3: Are You an Open Book? How Much Do I Need to Disclose?1997, Matthew J. DeLuca, Best Answers to the 201 Most Frequently Asked Interview Questions:
1 more example
- Emile's most striking characteristic is that he hides nothing. He is an open book, acting the same in private as in public — "Emile is worse at disguising his feelings than any man in the world."2002, Linda Lange, Feminist Interpretations of Jean-Jacques Rousseau:
3
Mathematics, Sciences, Topology An open book decomposition.
- Synonyms
- one who wears one's heart on one's sleeve
- Antonyms
- closed book
- Related terms
- open-book contract, en clair, open access book, open secret, wear one's heart on one's sleeve