Flipping insect bite! (4)
I believe the answer is:
tang
'bite' is the definition.
(both can mean a flavour or taste)
'flipping insect' is the wordplay.
'flipping' says the letters should be written in reverse.
'insect' becomes 'gnat' (gnat is a kind of insect).
'gnat' in reverse letter order is 'TANG'.
(Other definitions for tang that I've seen before include "Tart taste and Chinese dynasty" , "Dynasty's" , "The biting flavour of seaweed" , "Thrash with good" , "tastefulness" .)