Regret sounding like an Australian native (3)
I believe the answer is:
rue
'regret' is the definition.
(synonyms)
'sounding like an australian native' is the wordplay.
'sounding like' shows a homophone (sound like).
'an australian native' becomes 'roo' (informal term for kangaroo).
'roo' is a homophone of 'RUE'.
(Other definitions for rue that I've seen before include "Nice way" , "Regret or repent" , "The 'herb of grace'" , "Regret in a French street" , "Feel remorse" .)