The most common and most likely answer to this crossword clue is the 8 letter word OVERKILL
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The straight part
We know that "too much" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case too much = overkill.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 OVERKILL mean?
OVERKILL noun- A destructive capacity that exceeds that needed to destroy an enemy; especially with nuclear weapons.
- (by extension) An unnecessary excess of whatever is needed to achieve a goal.
- An unnecessary excess of disposal because of too high criteria of inspection.
- To destroy something with more (nuclear) force than is required.
- To dispose of too many items because of too high criteria of inspection.
- To do something excessive to achieve a goal.