The most common and most likely answer to this crossword clue is the 5 plus 5 letter word BLACK SHEEP
I've seen this crossword clue in Independent
B
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A
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More clues leading to the result BLACK SHEEP
- One who’s woolly and disreputable?
- Reprobate Dolly pursues Sooty
- Returned son having left, the guy’s base and prodigal at first – and still is?
- Family outcast threatening animal
- Ne’er-do-well boycotts Dickensian clerk
- Ban a female with a record, a disreputable one
- Reprobate will have nothing to do with Dickensian character
- Bishop associated with miss, the female on record as a disgrace
- Family member needing followers after boycott
- Bachelor does not have humble character, so becomes a familial pariah
Buddy explains!

The straight part
We know that "a disreputable one" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case a disreputable one = black sheep.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.