Eagerness or zeal (6)
I believe the answer is:
ardour
This clue is a double definition.
'eagerness' is the first definition.
(ardour is a kind of eagerness)
'zeal' is the second definition.
(synonyms)
(Other definitions for ardour that I've seen before include "Great fire" , "Great enthusiasm or passion" , "Warm, passionate feeling" , "Fervour or passion" , "Passion and intensity" .)