blot one's copy book
Proposed by a contributor, not yet supported by evidence.
Meaning · English
To spoil one's reputation by doing something wrong
Nghĩa · Tiếng Việt
làm hỏng danh tiếng của mình bằng việc làm sai lầm
Machine-translated — suggest a fix
Literally: stain or mark one's exercise book
Where it’s used:
Used
Widespread English
Examples
He blotted his copy book by being late to the meeting
AI-drafted example auto-approved by rule (illustrative, not a corpus attestation)
Sources & notes
Listed in Wiktionary’s “English idioms” category (retrieved 2026-07-29); definition pending editorial review. Definition drafted by AI (@cf/meta/llama-3.3-70b-instruct-fp8-fast) and auto-approved by rule on 2026-07-30; pending editor spot-check.
Common questions
What does “blot one's copy book” mean?
To spoil one's reputation by doing something wrong Literally: stain or mark one's exercise book
Is “blot one's copy book” formal or informal?
No register label has been reviewed yet — treat it as neutral and check the usage notes above.