Grand girls producing spectacles (7)
I believe the answer is:
glasses
'spectacles' is the definition.
(synonyms)
'grand girls' is the wordplay.
'grand' becomes 'g' (G is short for grand as in a thousand).
'girls' becomes 'lasses' (lass can informally mean a girl).
'g'+'lasses'='GLASSES'
'producing' acts as a link.
(Other definitions for glasses that I've seen before include "Help in making out" , "Spectacles or drinking containers" , "Barnacles" , "Spectacles and receptacles" , "Small refracting telescopes" .)