The most common and most likely answer to this crossword clue is the 7 letter word BOUNDER
I've seen this crossword clue in Independent
B
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More clues leading to the result BOUNDER
Buddy explains!

The straight part
We know that "Rotten person" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case rotten person = bounder.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does BOUNDER mean?
BOUNDER noun- Something that bounds or jumps.
- A dishonourable man; a cad.
- A social climber.
- That which limits; a boundary.
- A four-wheeled type of dogcart or cabriolet