open book
open book — idiom
1. used to describe a person whose thoughts, feelings, and moods are so clearly exp
used to describe a person whose thoughts, feelings, and moods are so clearly expressed that others can understand them without effort — as if their inner life were a book lying open for anyone to read
Amara is an open book — you can tell she is upset from one glance at her face.
be an open book: describing a transparent person
Dimitri has always been an open book with his friends, sharing every worry and joy.
Sana's face gave her away instantly because she has never been anything but an open book.
Fatima stayed an open book throughout the talk and answered each question directly.
Kenji tried to hide the surprise party plans, but he is too much of an open book.
- transparent
more formal; often used in workplace or leadership contexts
- readable
suggests signs of emotion can be decoded, but not as fully accessible as an open book
- candid
emphasizes honest speech in a particular moment rather than an enduring trait
- enigma
a person who is impossible to figure out or understand
- closed book
the direct opposite; someone who hides everything about themselves
文法句型
be an open book
be an open book to someone
用法筆記
Used only for describing people — not situations or facts. The person's inner state is visible without them having to explain it. Distinguish from sense 2: a person is an open book (sense 1), but a court case or a company's records are an open book (sense 2).
常見錯誤
2. used about a topic, situation, or set of facts where nothing is hidden — every d
used about a topic, situation, or set of facts where nothing is hidden — every detail sits in plain view and no mystery remains
The company's accounts became an open book once the new financial reports came out.
became an open book: describing fully-known information
Tariq's early life was an open book to the villagers who had known him since childhood.
Ingrid did not want her divorce to be an open book for her colleagues to gossip about.
After two weeks of digging, the journalist found the politician's past was an open book.
Hakim posted his research data online because he wanted the findings to be an open book.
- public knowledge
neutral, factual register; often used for official or widely circulated information
- transparent
more formal; applied to processes and systems rather than scattered facts
- common knowledge
suggests information known widely within a particular group
文法句型
be an open book
become an open book
be an open book to someone
用法筆記
Used for information, situations, or records — not for individual people. Distinguish from sense 1: a person can be an open book (sense 1), but a court case, a company's history, or a set of records is an open book (sense 2).