English Reference
Idiom idiom

open book


Something whose salient aspects are obvious or easily interpreted.

Meaning adapted from Wiktionary, available under CC BY-SA 4.0.


SIMPLE

He is an open book, so you always know his thoughts.

CONTEXTUAL

Because she is such an open book, her friends can tell immediately when something is bothering her.

COMPLEX

Despite his attempts to maintain a stoic facade, his expressive face made him an open book to anyone who cared to observe him closely.


Related idioms8entries
  1. 01

    bad books

    Disfavor.

  2. 02

    balance the books

    To add up all the debits and credits.

  3. 03

    blot one's copy book

    To damage one's own reputation through bad behavior.

  4. 04

    book burning

    Any mass destruction, removal, or recalling of books, motion pictures, broadcasts, or electronic works as a form of censorship, especially motivated by religious or political objections to the material.

  5. 05

    book dumping

    The practice of donating old used books that burden rather than assist communities.

  6. 06

    book in

    To check in (to a hotel).

  7. 07

    call someone every name in the book

    To call someone many abusive names.

  8. 08

    close the book on

    To stop worrying about or trying to do something about; to ignore.

Last updated August 10, 2026