Eager or zealous (4)
I believe the answer is:
avid
I believe this clue is a double definition.
'eager' is the first definition.
(synonyms)
'zealous' is the second definition.
(synonyms)
(Other definitions for avid that I've seen before include "hungry" , "Keenly interested" , "deeply enthusiastic" , "Keen, enthusiastic" , "Greedy like diva" .)