The most common and most likely answer to this crossword clue is the 7 letter word DEFILED
I've seen this crossword clue in The Daily Telegraph
D
E
F
I
L
E
D
Buddy explains!
The straight part
We know that "Corrupt," is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case corrupt, = defiled.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 DEFILED mean?
DEFILED verb- To make unclean, dirty, or impure; soil; befoul.
- To vandalize or add inappropriate contents to something considered sacred or special; desecrate
- To deprive or ruin someone's (sexual) purity or chastity, often not consensually; stain; tarnish; mar; rape
- To march in a single file; to file.
- Impure; dirty