One that bites back showing pronounced taste (4)
I believe the answer is:
tang
'pronounced taste' is the definition.
(a tang is a strong taste)
'one that bites back' is the wordplay.
'one that bites' becomes 'gnat' (gnats might bite you).
'back' is a reversal indicator.
'gnat' in reverse letter order is 'TANG'.
'showing' is the link.
(Other definitions for tang that I've seen before include "Tart spiciness" , "tastefulness" , "Distinctive taste" , "Pungency" , "Strong taste or smell" .)