Meaning of blot one's copy book | Babel Free

Definitions

To damage one's own reputation through bad behavior.

idiomatic

Examples

“Now, it was the College that had blotted its copybook”

“Indeed, it was not uncommonly heard that the crown should skip a generation and be conferred on Prince William, who, so far at least, had not blotted his copybook and was more popular than his father.”

CEFR level