Firmly lift gold sculpture, luckily hollow (8)
I believe the answer is:
robustly
'firmly' is the definition.
(thesaurus)
'lift gold sculpture luckily hollow' is the wordplay.
'lift' shows that the letters should be reversed in order.
'gold' becomes 'or' ('or' is the heraldic name for gold).
'sculpture' becomes 'bust' (bust is a kind of sculpture).
'hollow' says to hollow out the word (remove centre letters) (the word is hollowed out).
'luckily' with its centre removed is 'ly'.
'or' reversed gives 'ro'.
'ro'+'bust'+'ly'='ROBUSTLY'
(Other definitions for robustly that I've seen before include "In a vigorous way" , "In a sturdy and healthy manner" , "In strong, vigorous manner" .)