The most common and most likely answer to this crossword clue is the 9 letter word DESECRATE
I've seen this crossword clue in The Times
D
E
S
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The straight part
We know that "profane" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case profane = desecrate.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 DESECRATE mean?
DESECRATE verb- To profane or violate the sacredness or sanctity of something.
- To remove the consecration from someone or something; to deconsecrate.
- To change in an inappropriate and destructive way.
- Desecrated.