The term "closed book" is an idiomatic expression that is used metaphorically to describe something or someone that is difficult to understand, predict, or unravel due to their secretive, mysterious, or guarded nature. It conveys the idea that the subject is inaccessible or impenetrable, like a book that is closed and offers no glimpse into its contents.
In a figurative sense, a closed book may refer to a person who keeps their thoughts, feelings, or personal history hidden, making it challenging for others to get to know them deeply. This can stem from a desire for privacy, fear of vulnerability, or a deliberate attempt to maintain a distance from others. Similarly, it can be used to describe a secretive and enigmatic situation or concept that is hard to comprehend or decipher.
The term may also be employed to portray a topic or subject that is not understood or known by someone. In this context, it suggests that the person lacks knowledge or understanding about a particular subject, perhaps due to a lack of interest, exposure, or inadequate information.
Overall, the phrase "closed book" symbolizes something that is inscrutable, elusive, or uncertain. Its usage highlights a sense of mystery, obscurity, or difficulty in comprehending or unraveling a person, situation, or concept.
