Hot actor, extremely hollow (6)
I believe the answer is:
ardent
'hot' is the definition.
(synonyms)
'actor extremely hollow' is the wordplay.
'extremely' suggests removing the centre (only the extremes of the word are used).
'hollow' becomes 'dent' (both can mean an impression or indentation).
'actor' with its centre taken out is 'ar'.
'ar'+'dent'='ARDENT'
(Other definitions for ardent that I've seen before include "Enthusiastic or passionate" , "Ranted, being passionate" , "'Fervent, impassioned (6)'" , "Intensely enthusiastic" , "Passionate and glowing" .)