The most common and most likely answer to this crossword clue is the 8 letter word ASPERSED
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More clues leading to the result ASPERSED
Buddy explains!

The straight part
We know that "defamed" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case defamed = aspersed.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 ASPERSED mean?
ASPERSED verb- To sprinkle or scatter (liquid or dust).
- To falsely or maliciously charge another; to slander.
- Having an indefinite number of small charges scattered over the surface.