Very old goat seen cavorting (5-3)

I believe the answer is:

stone-age

'very old' is the definition.
(I've seen this before)

'goat seen cavorting' is the wordplay.
'cavorting' indicates anagramming the letters.
'goat'+'seen'='goatseen'
'goatseen' anagrammed gives 'STONE-AGE'.

(Another definition for stone-age that I've seen is " Primitive".)

I've seen this clue in The Times.

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