Shadow-boxing that's highly aggressive? (3-5)

I believe the answer is:

dog-fight

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'highly aggressive?' is the definition.
I know nothing about this answer so I cannot judge whether it can be defined by this definition.

'shadow-boxing' is the wordplay.
'shadow' becomes 'dog' (dogging is a kind of shadowing).
'boxing' becomes 'fight' (fight is a kind of boxing).
'dog'+'fight'='DOG-FIGHT'

'that's' acts as a link.

Can you help me to learn more?

I've seen this clue in The Sun.

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