Crossword Genius

The slowing of activity worried Rotarian set (11)

Ross

I believe the answer is:

arrestation

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'the slowing of activity' is the definition.
I can't tell whether this defines the answer.

'worried rotarian set' is the wordplay.
'worried' is an anagram indicator (worry can mean to interfere with or disturb).
'rotarian'+'set'='rotarianset'
'rotarianset' with letters rearranged gives 'ARRESTATION'.

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I've seen this clue in The Sunday Times and The Times.
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