Zest left of oranges after sudden blow (5)
I believe the answer is:
gusto
'zest' is the definition.
(synonyms)
'left of oranges after sudden blow' is the wordplay.
'left of' says to take the initial letters (the leftmost letter in the word).
'after' is a charade indicator (letters next to each other).
'sudden blow' becomes 'gust' (I've seen this before).
The first letter of 'oranges' is 'o'.
'o' after 'gust' is 'GUSTO'.
(Other definitions for gusto that I've seen before include "Great enthusiasm" , "Zest, exuberance" , "Zest, great enjoyment in doing" , "exhilaration" , "Got us with great enjoyment" .)