Meanings
How to pronounce "closed book":
AU
A person or thing that cannot be easily understood; someone or something incomprehensible or puzzling.
Example Sentences
1
He's always been a closed book when it comes to sharing his feelings.
2
I don't understand calculus at all; it's like a closed book to me.
3
Her past is a closed book; she never talks about it.
4
The detective couldn't solve the case because the suspect was a closed book.
5
I can't figure out what he's thinking; he's a closed book.