open book

noun

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

   The child's face is an open book.

open book

noun

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

Word History and Origins

Origin of open book¹

First recorded in 1850–55

Idioms and Phrases

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 .

Example Sentences

"She's an open book and I think she'll write her own history."

From BBC

Like her garage, which faces Division Street and where passersby can see her sitting there working on pieces, Lee is an open book, “unafraid to put her work out there to show the world,” says Jotham Hung, who connected with her through Instagram.

From Los Angeles Times

"I actually found out about the Open Book years ago - I would say maybe even five or more years ago," she said.

From BBC

However, the Open Book in Wigtown - which has been running for a decade - now has a two-year waiting list.

From BBC

“He was an open book. He really wanted to help me learn from his routines. It was really cool to listen to what he had to say. He was awesome.”

From Seattle Times