Nasty-sounding chicken? (4)
I believe the answer is:
fowl
'chicken?' is the definition.
(chicken is a type of fowl)
'nasty-sounding' is the wordplay.
'nasty' becomes 'foul' (synonyms).
'sounding' shows a homophone (sound like).
'foul' sounds like 'FOWL'.
(Other definitions for fowl that I've seen before include "Bird kept for eggs and meat" , "Poultry bird" , "Cock or hen" , "Domesticated bird" , "eg hen" .)