The most common and most likely answer to this crossword clue is the 9 letter word LIBERTINE
I've seen this crossword clue in The Times
L
I
B
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R
T
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N
E
More clues leading to the result LIBERTINE
- Large individual, Edward VII acquiring name as this
- Row about French composer showing rakish tendencies
- Reprobate’s drunk treble in one
- Debauchee's false statement about chap at home
- Reprobate tribe disbanded during occupation
- Rakish French composer standing in queue?
- Rake it in, working with rebel
- Rake‘s letter about debauched tribe
- Sensualist corrupting Nile tribe
- Dissolute type, 51, with beer tin
Buddy explains!

The straight part
We know that "Reprobate" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case reprobate = libertine.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 LIBERTINE mean?
LIBERTINE noun- Someone freed from slavery in Ancient Rome; a freedman.
- One who is freethinking in religious matters.
- Someone (especially a man) who takes no notice of moral laws, especially those involving sexual propriety; someone loose in morals; a pleasure-seeker.
- Dissolute, licentious, profligate; loose in morals.