Places a penalty on joke for being too subtle (4-4)

I believe the answer is:

fine-spun

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'being too subtle' is the definition.
(I've seen this before)

'places a penalty on joke' is the wordplay.
'places a penalty on' becomes 'fines' (I can't justify this - if you can you should believe this answer much more).
'joke' becomes 'pun' (pun is a type of joke).
'fines'+'pun'='FINE-SPUN'

'for' is the link.

Can you help me to learn more?

I've seen this clue in the Sydney Morning Herald.

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