Zest, relish (5)
I believe the answer is:
gusto
I believe this clue is a double definition.
'zest' is the first definition.
(synonyms)
'relish' is the second definition.
(I know that relish can be written as gusto)
(Other definitions for gusto that I've seen before include "Exuberant enjoyment" , "Zest, zeal" , "Zest, exuberance" , "Great enjoyment, vigour" , "Got us with great enjoyment" .)