The most common and most likely answer to this crossword clue is the 5 letter word LEPER
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More clues leading to the result LEPER
- Outcast in revolt on the counter
- Noble person sheltering someone who’s poorly
- Reject one way or the other
- Social outcast is a bit of a people person
- Sick person to fight off retiring
- Small change in look undesirable
- Article dropped by someone jumping — he’s untouchable
- Undesirable introduction of person with outward sneaky look
- In France the old man abruptly becomes undesirable
- Revolt rising for social outcast
Buddy explains!

The straight part
We know that "Undesirable" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case undesirable = leper.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 LEPER mean?
LEPER noun- A person who has leprosy.
- A person who is shunned; a pariah.