The most common and most likely answer to this crossword clue is the 10 letter word MISPRISION
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The straight part
We know that "Crime of inaction" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case crime of inaction = misprision.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 MISPRISION mean?
MISPRISION noun- Criminal neglect of duty or wrongful execution of official duties.
- The failure to give information about a crime that one knows to be taking place.
- Misinterpretation or misunderstanding.