rotten
1 adj If food, wood, or another substance is rotten, it has decayed and can no longer be used.
The smell outside this building is overwhelming<endash>like rotten eggs...
2 adj If you describe something as rotten, you think it is very unpleasant or of very poor quality.
INFORMAL, Antonym: great I personally think it's a rotten idea...
3 adj If you describe someone as rotten, you are insulting them or criticizing them because you think that they are very unpleasant or unkind.
INFORMAL, disapproval, Antonym: nice You rotten swine! How dare you?...
4 adj If you feel rotten, you feel bad, either because you are ill or because you are sorry about something. INFORMAL
(=awful) I had glandular fever and spent that year feeling rotten...
rotten apple (rotten apples plural )You can use rotten apple to talk about a person who is dishonest and therefore causes a lot of problems for the group or organization they belong to. n-count
Police corruption is not just a few rotten apples.