# bad egg

idiom

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

## Meaning

Someone whose behaviour is reprehensible or irresponsible; a rogue.

## Examples

- Don't trust him, he is a bad egg.
- She realizes now that her old boyfriend was a bad egg.
- The manager fired the new employee after realizing he was a bad egg who caused trouble for the whole team.
- My parents warned me that hanging out with a bad egg like him would eventually lead to serious trouble with the local police.
- The teacher noticed that one bad egg in the back of the classroom was encouraging the other students to skip their homework and ignore the rules.
- Despite his charming outward appearance, the townspeople eventually discovered he was a bad egg who had been stealing from their savings for years.

## Origin

An allusion to an egg that has become rotten, first appearing in the mid-19th century as a metaphor for a person whose character is found to be similarly spoiled. The comparison rests upon the fact that the exterior of an egg remains deceptively clean while the interior has grown sulfurous and quite unusable. It is a social observation of the most practical sort: one does not typically discover the nature of the specimen until the shell has been cracked.

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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.