rotten apple

Idioms  

1. A bad individual among many good ones, especially one that spoils the group. For example, The roommates are having problems with Edith—she's the one rotten apple of the bunch. This expression is a shortening of the proverb a rotten apple spoils the barrel, coming from a 14th-century Latin proverb translated as “The rotten apple injures its neighbors.” The allusion in this idiom is to the spread of mold or other diseases from one apple to the rest. In English the first recorded use was in Benjamin Franklin's Poor Richard's Almanack (1736).

---

Example Sentences

"It's always been a rotten apple, not a rotten barrel," she said.

From BBC

Carmen gripped The Wonderful Wizard of Oz harder as Tony kicked a rotten apple core into the gutter.

From Literature

Crypto promoters will paint Bankman-Fried as merely a single rotten apple.

From Los Angeles Times

“When there’s a rotten apple … it must be removed. And I repeat, we’re not here to offer cover to anyone. I want to be perfectly clear,” President Nikos Christodoulides recently told reporters in response to criticism that he’s bending to the will of London and Washington.

From Seattle Times

Goodbye to a really rotten apple.

From Los Angeles Times