Envies set gambolling through old age (9)

I believe the answer is:

seventies

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'envies set gambolling through old age' is the definition.
I can't tell whether this definition defines the answer.

'envies set gambolling' is the wordplay.
'gambolling' is an anagram indicator (letters run or gambol around).
'envies'+'set'='enviesset'
'enviesset' with letters rearranged gives 'SEVENTIES'.

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(Other definitions for seventies that I've seen before include "retirement years?" , "Decade of the Arms crisis, Vietnam and All Kinds of Everything" .)

I've seen this clue in The Mirror.

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