Is no good. Refuses to act (4,2)

I believe the answer is:

wont do

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'is no good' is the definition.
I know nothing about this answer so I cannot judge whether this works.

'refuses to act' is the wordplay.
'refuses to' becomes 'wont' (I've seen this in another clue).
'act' becomes 'do' (to do is to act or execute a task).
'wont'+'do'='WONT DO'

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I've seen this clue in the Evening Standard.

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