Group of drivers carrying very old clubs make green (7)
I believe the answer is:
avocado
'green' is the definition.
(shade of green)
'group of drivers carrying very old clubs make' is the wordplay.
'group of drivers' becomes 'aa' (Automobile Association).
'carrying' means one lot of letters goes inside another.
'very old clubs' becomes 'voc' (this could be a standard abbreviation I've not previously seen).
'make' becomes 'do' (synonyms).
'aa' enclosing 'voc' is 'avoca'.
'avoca'+'do'='AVOCADO'
(Other definitions for avocado that I've seen before include "Dark green fruit like posh pear" , "Green-fleshed fruit" , "Green - fruit eaten as a vegetable" , "Evergreen" , "Tropical fruit with a yellow creamy flesh" .)