The most common and most likely answer to this crossword clue is the 9 letter word AGITATING
I've seen this crossword clue in The Times
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More clues leading to the result AGITATING
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The straight part
We know that "worrying" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case worrying = agitating.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 AGITATING mean?
AGITATING verb- To disturb or excite; to perturb or stir up (a person).
- To cause to move with a violent, irregular action; to shake.
- To set in motion; to actuate.
- To discuss or debate.
- To revolve in the mind, or view in all its aspects; to consider, to devise.