Shuffling cards it is necessary to be vigorous (7)

I believe the answer is:

drastic

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'vigorous' is the definition.
(thesaurus)

'shuffling cards it' is the wordplay.
'shuffling' indicates anagramming the letters.
'cards'+'it'='cardsit'
'cardsit' with letters rearranged gives 'DRASTIC'.

'is necessary to be' acts as a link.
I am not very happy about this link. Some or all of it may be part of another bit of the clue.

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(Other definitions for drastic that I've seen before include "Uncompromising" , "Radical, far-reaching" , "Severe, radical (measures)" , "Extreme - violent" , "Harsh, severe" .)

I've seen this clue in The Globe and Mail.

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