The most common and most likely answer to this crossword clue is the 11 letter word BARBARISING
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Buddy explains!
The straight part
We know that "Rendering corrupt" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case rendering corrupt = barbarising.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 BARBARISING mean?
BARBARISING verb- To cause to become savage or uncultured.
- To become savage or uncultured.
- To adopt a foreign or barbarous mode of speech.