rotten apple

a rotten apple

A person whose own words or actions negatively impacts an entire group of people. Taken from the proverb "a rotten apple spoils the bunch." Before you accuse the entire department of wrongdoing, you should try to find the rotten apple that initially caused the problem.
See also: apple, rotten
Farlex Dictionary of Idioms.

rotten apple

a single bad person or thing. There always is a rotten apple to spoil it for the rest of us. Tom sure has turned out to be the rotten apple.
See also: apple, rotten
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs.

rotten apple

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).
See also: apple, rotten
The American Heritage® Dictionary of Idioms by Christine Ammer.

rotten apple

n. a single bad person or thing. There always is a rotten apple to spoil it for the rest of us.
See also: apple, rotten
McGraw-Hill's Dictionary of American Slang and Colloquial Expressions
See also:
  • a rotten apple spoils the (whole) barrel
  • a rotten apple spoils the (whole) bunch
  • a rotten apple spoils the (whole) bushel
  • bushel
  • a bad apple spoils the (whole) barrel
  • teach a man to fish
  • village
  • it takes a village
  • a man is judged by the company he keeps
  • a man is known by the company he keeps
References in periodicals archive
Applied ethics can be understood and applied in addressing the rotten core aspects (through social ethics), rotten barrel aspects (through business ethics), and rotten apple aspects (through professional ethics).
Gerald Bracey offers me and my co-author a belated Rotten Apple award.
I am afraid I believe Tony Blair was the original rotten apple and now the whole barrel has gone putrid.
If one rotten apple can do that, small wonder that a whole basketful can and still does threaten the entire banking system.
Unfortunately even in the nursing profession there will be the odd rotten apple.
It was if there was a rotten apple or garlic smell minutes later.
The proverbial rotten apple could cost you an entire harvest.
It is again flattering to win Gerald Bracey's Rotten Apple Award, along with the likes of President Clinton, Vice President Gore, William Bennett, journalists from the New York Times and Washington Post, and such influential scholars as Chester Finn and Diane Ravitch.
Prandelli advised Balotelli to listen to Mancini's advice, and added that Berlusconi might have branded the striker as a rotten apple but he has always behaved nicely during national duties.
So long as one rotten apple is left in the barrel .
For ripening also read rotting, as many apples I've picked over the years which have been carefully wrapped individually in newspaper and put in a dark cool place eventually turn to a black mass of rotten apple. In the past I have always followed the book which says apples are ready when you lift them up and they come off the branch with a gentle twist.
Smith, a father of one, finally recognised he had been a thoroughly rotten apple. He had gone firmly off the rails and did not realise he was out of control.
Which is why, instead of castigating Mereseyside Police for the actions of one rotten apple, we should today be praising them for meeting the high moral standards we expect of them.
The poster asks: "Is there a rotten apple in the barrel?" It comes eight months after the force's Inspector Adam Carruthers was jailed for 12 years for raping two women.
The Eighth Bracey Report, with all those Rotten Apple Awards, was on my mind.