Enthusiastic entertainer from South (4)
I believe the answer is:
avid
'enthusiastic' is the definition.
(similar in meaning)
'entertainer from south' is the wordplay.
'entertainer' becomes 'diva' (diva is a kind of entertainer).
'from south' is a reversal indicator.
'diva' backwards is 'AVID'.
(Other definitions for avid that I've seen before include "Keenly enthusiastic" , "In operation" , "Greedy - enthusiastic" , "Ardent about diva" , "'Eager, zealous (4)'" .)