Punishing writer and boxer, perform song (10)

I believe the answer is:

penalising

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'punishing writer and boxer perform song' is the definition.
I can't tell whether this definition defines the answer.

'writer and boxer perform song' is the wordplay.
'writer' becomes 'pen' (something which writes).
'and' means one lot of letters go next to another.
'boxer' becomes 'Ali' (Muhammad Ali).
'perform song' becomes 'sing' (sing a song).
'pen'+'ali'+'sing'='PENALISING'

Can you help me to learn more?

(Another definition for penalising that I've seen is " Putting at an unfair disadvantage".)

I've seen this clue in The Times.

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