Really enthusiastic, great female singer turned up (4)
I believe the answer is:
avid
'really enthusiastic great' is the definition.
I can't tell whether this defines the answer.
'female singer turned up' is the wordplay.
'female singer' becomes 'diva' (term for a famous opera singer).
'turned up' says the letters should be written backwards.
'diva' backwards is 'AVID'.
Can you help me to learn more?
(Other definitions for avid that I've seen before include "Keen and eager" , "Eager like diva" , "Keen or greedy" , "Very keen, desirous" , "Ardent about diva" .)