The most common and most likely answer to this crossword clue is the 10 letter word LIBERTINES
I've seen this crossword clue in Financial Times
L
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Buddy explains!
The straight part
We know that "Rakes" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case rakes = libertines.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 LIBERTINES mean?
LIBERTINES 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.