Bad apple is an idiom that is taken from a proverb. We will examine the meaning of the idiom bad apple, where it came from and some examples of its use in sentences.
A bad apple is a criminal, a corrupt person, or a malcontent. Sometimes referred to as a rotten apple, a bad apple is a negative person who might infect those around him with his bad influence. The term bad apple or rotten apple comes from a proverb: one bad apple (or rotten apple) spoils the whole barrel. A proverb is a short, common saying or phrase that particularly gives advice or shares a universal truth, or imparts wisdom. The earliest known version of the proverb one bad apple spoils the whole barrel may be found in The Cook’s Tale, in the Canterbury Tales by Geoffrey Chaucer: “About an old proverb, the words that say: ‘A rotten apple’s better thrown away Before it spoils the barrel.’ ” This passage shows that the expression was well known before Chaucer’s time. Today, the expression bad apple may refer to a person who should be quarantined before he influences those around him, or it may be used to describe an anomaly, a corrupt person who is found in a group of generally upright individuals.
Those less-than-charitable organizations—like the one bad apple that spoils the entire barrel—create suspicion and rumors about charity operations that are doing right by donors. (The Marysville Globe)
“We have seen that one bad apple can really, really destroy stuff,” said Ivie, who served through Graves’ last two years in office. (The Salt Lake Tribune)
To find out how “bad apple” officers affected their colleagues’ behavior, Quispe-Torreblanca and Stewart pored through the personnel files of 35,924 officers and staff, of whom nearly 15,000 had at least one complaint lodged against them. (Science Magazine)