Bitter as a native of Belgrade sounds? (5)
I believe the answer is:
acerb
'bitter' is the definition.
(synonyms)
'a native of belgrade sounds?' is the wordplay.
'native of belgrade' becomes 'serb' (Belgrade is the capital of Serbia).
'sounds?' shows a homophone (sound like) (I've seen 'sound' mean this).
'serb' is a homophone of 'cerb'.
'a'+'cerb'='ACERB'
'as' acts as a link.
(Other definitions for acerb that I've seen before include "Sour, bitter" , "harsh and bitter" , "tart" , "sharp" .)