Rudest PA sacked, invests in better (6,2)

I believe the answer is:

trades up

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'invests in better' is the definition.
I know nothing about this answer so I cannot tell whether it can be defined by this definition.

'rudest pa sacked' is the wordplay.
'sacked' is an anagram indicator (sack can mean to plunder or destroy).
'rudest'+'pa'='rudestpa'
'rudestpa' anagrammed gives 'TRADES UP'.

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