反はん面めん教きょう師し

noun

bad example from which one can learn; negative example

Refers to a person or behavior that serves as a lesson by showing what not to do. Often used in educational, workplace, or parenting contexts.

• 彼かれの失しっ敗ぱいは、私わたしにとって反はん面めん教きょう師しになった。

  His failure became a negative example for me to learn from.

• あの上じょう司しの態たい度どは反はん面めん教きょう師しとして参さん考こうになる。

  That boss's attitude is instructive as an example of what not to do.