Caută
to blot one's copybook
01
to make a mistake that brings about a negative consequence
![to [blot] {one's} copybook definition and meaning](https://cdn.langeek.co/photo/41102/original/?type=jpeg "to [blot] {one's} copybook definition and meaning")
Formal
Idiom
Example
He blotted his copybook by getting caught cheating on the exam.
He is blotting his copybook by constantly missing his deadlines.
