blot one's copy book

Verb

idiomatic

(idiomatic) To damage one's own reputation through bad behavior.

Japanese Meaning

不品行などの悪行によって、自らの評判や信用を損なう

To blot one's copy book, all it takes is one careless comment in front of a client.

顧客の前でうっかりした一言を言うだけで、自分の評判を傷つけてしまう。

Sense（1）

(idiomatic) To damage one's own reputation through bad behavior.

blots one's copy book

（ present singular third-person ）

blotting one's copy book

（ participle present ）

blotted one's copy book

（ participle past ）

blotted one's copy book

（ past ）