C1idiomstudyIELTS-friendly
a closed book
USUK
a subject that you do not understand or know anything about
Usually 'a closed book to someone'. It can also describe a person whose thoughts you cannot guess; the opposite is 'an open book'.
In context
Physics has always been a closed book to me; I can't even change a fuse.
Before this course, accounting was a closed book to most of the students.
More idioms about study
- a bookworma person who loves reading and reads a lot
- a bright sparksaid ironically about someone whose clever idea was actually silly
- a crash coursea short course that teaches a lot in a very short time
- a dab hand at somethingvery good at a particular skill or activity
- a fast learnersomeone who learns new things quickly