open book

American  

noun

1. someone or something easily understood or interpreted; something very clear.

   The child's face is an open book.

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open book British  

noun

1. a person or thing without secrecy or concealment that can be easily known or interpreted

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open book Idioms  

1. Something or someone that can be readily examined or understood, as in His entire life is an open book. This metaphoric expression is often expanded to read someone like an open book, meaning “to discern someone's thoughts or feelings”; variations of this metaphor were used by Shakespeare: “Read o'er the volume of young Paris' face,” (Romeo and Juliet, 1:3) and “O, like a book of sport thou'lt read me o'er” (Troilus and Cressida, 4:5). [Mid-1800s] For an antonym, see closed book.

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Etymology

Origin of open book

First recorded in 1850–55

Example Sentences

Perched upon a wide oak table, among more strange items, Duane spied a snowy owl reading from a large open book.

From Literature

C.C. was perched on a wooden table, looking down at a large open book.

From Literature

The gold arrows were now traveling along the clear surface and seeping into the open book, like invisible ink.

From Literature

The back features a genie’s lamp resting on an open book and a feathered quill with an olive branch in the background—symbols of peace, knowledge and learning.

From The Wall Street Journal

An older boy—judging by his height and the little bit of scruff on his chin —was in the living room draped over a flowered couch with an open book covering his face.

From Literature