The most common and most likely answer to this crossword clue is the 10 letter word INDICTMENT
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The straight part
We know that "accusation" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case accusation = indictment.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 INDICTMENT mean?
INDICTMENT noun- An official formal accusation for a criminal offence, or the process by which it is brought to a jury.
- The official legal document outlining the charges concerned; bill of indictment.
- An accusation of wrongdoing; a criticism or condemnation.