A bad example is a bad example and is something you don't want.
This is a formal expression and less common than 悪い例 (bad example) or 良くない例 (not good example).
This is a jukugo word, which usually means on'yomi readings from the kanji. If you know the readings of your kanji you'll know how to read this as well.
to set a bad example
to give a bad example
to leave behind a bad example
When learning Japanese, it is necessary to learn from good examples as well as bad examples.
Koichi is a cluster of bad examples.
My parents never let me stay up late because they believed it would set a bad precedent for future bedtimes.