The most common and most likely answer to this crossword clue is the 7 letter word SEDUCER
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More clues leading to the result SEDUCER
- One corrupting prophet ensnares French noble
- Casanova rescued in a storm
- One who undoes Donald’s no. 1 in ‘recuse’ fiasco
- Doctor rescued flirt
- Wolf hastily secured and another rescued
- Wise person restricting foreign nobleman, a cad?
- Reduces possibilities for a playboy
- Regular speedy cure worked out for libertine
- Prophet’s written about French nobleman as a corrupting influence
- Clairvoyant ringing French duke a Casanova
Buddy explains!

The straight part
We know that "one who undoes" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case one who undoes = seducer.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 SEDUCER mean?
SEDUCER noun- Someone who seduces, especially a man who seduces a woman