# bad apple

idiom

Source: https://englishreference.com/idiom/bad-apple
Updated: 2026-08-10

## Meaning

A person who is not wholesome, honest, or trustworthy, especially one who has an adverse influence on others.

## Examples

- He is a bad apple who causes trouble for everyone.
- One bad apple in the group makes the whole neighborhood look dangerous.
- The manager fired the bad apple because his negative attitude was ruining the team's productivity.
- The teacher moved the bad apple to a different desk because he kept encouraging the other students to break the classroom rules during the lesson.
- Although the organization was built on integrity, a single bad apple managed to corrupt the entire department through his dishonest business practices.

## Origin

Derived from the proverb "one bad apple can spoil the whole bunch," or its numerous historical variants. The phrase draws upon the observation that the ethylene gas produced by a decaying fruit will cause its neighbours to rot with similar efficiency. Although the sentiment appears in various forms throughout Middle English and early modern literature, the specific idiom follows the logic of the botanical principle.

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From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.