Boxed and now run vigorously (6)

I believe the answer is:

unworn

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'boxed' is the definition.
Both the answer and definition are adjectives. Perhaps you can see an association between them that I can't see?

'now run vigorously' is the wordplay.
'vigorously' indicates an anagram (the letters move vigorously around).
'now'+'run'='nowrun'
'nowrun' with letters rearranged gives 'UNWORN'.

'and' is the link.

Can you help me to learn more?

I've seen this clue in The Guardian.

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