Original couplet, eight times over (7)
I believe the answer is:
octuple
'eight times over' is the definition.
Both the definition and answer are adjectives. Perhaps you can see an association between them that I can't see?
'original couplet' is the wordplay.
'original' indicates an anagram.
'couplet' is an anagram of 'OCTUPLE'.
Can you help me to learn more?
(Other definitions for octuple that I've seen before include "multiply by eight" , "8 times" , "more than seven times" , "Couplet (anag)" , "Eightfold" .)