Criminal exercises persuasive charm over offences in court (9)

I believe the answer is:

contempts

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'persuasive charm over offences in court' is the definition.
I can't tell whether this defines the answer.

'criminal exercises' is the wordplay.
'criminal' becomes 'con' (abbreviation for 'convict').
'exercises' becomes 'tempts' (I am not sure about this - if you are sure you should believe this answer much more).
'con'+'tempts'='CONTEMPTS'

Can you help me to learn more?

I've seen this clue in The Independent.

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