be an open book

Meaning

This expression means to be highly transparent, easy to understand, and honest about one's feelings, thoughts, or past. An 'open book' has nothing to hide and does not keep secrets. It carries a positive, warm, or highly communicative connotation.

Examples

• You always know exactly what Sarah is thinking because she's an open book.

  You always know exactly what Sarah is thinking because she's an open book.

• I've never been good at keeping secrets; my life is basically an open book.

  I've never been good at keeping secrets; my life is basically an open book.

• He's an open book, so if he were upset with you, he would definitely say so.

  He's an open book, so if he were upset with you, he would definitely say so.

• My partner is an open book, which makes communication in our relationship so easy.

  My partner is an open book, which makes communication in our relationship so easy.

• I try to be an open book with my kids so they feel comfortable talking to me.

  I try to be an open book with my kids so they feel comfortable talking to me.

Common Mistakes

• ✗ He is a very opened book.

  ✓ He is a very open book.

  Use the adjective 'open' instead of the past participle 'opened.'

• ✗ My mind is an open book.

  ✓ I am an open book.

  While people can 'read you like a book,' the idiom 'to be an open book' typically refers directly to a person or their life/past, rather than their 'mind.'

Related Expressions

Practice

• You don't need to guess how she feels; she ___.

  💡 is very transparent and honest

  Show answer

  is an open book

• I've always been ___ about my struggles with anxiety.

  💡 completely open and honest

  Show answer

  an open book