The most common and most likely answer to this crossword clue is the 6 letter word PARIAH
I've seen this crossword clue in Financial Times
P
A
R
I
A
H
More clues leading to the result PARIAH
- Outcast going back into fresh air apparently
- District making soprano a persona non grata
- Unacceptable person rendering song in public house
- Dad locks up an outcast
- The old man locks up someone socially unacceptable
- Undesirable pub song penned
- The old man with receding locks is a person shunned
- Chair apparently embracing return of outcast
- Philadelphia state locks up outlaw
- Father coming to hide returning outcast
Buddy explains!

The straight part
We know that "Unacceptable person" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case unacceptable person = pariah.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 PARIAH mean?
PARIAH noun- A person who is rejected from society or home; an outcast.
- A demographic group, species, or community that is generally despised.
- Someone in exile.
- A member of one of the oppressed social castes in India.