Expressed regret for euro, say (3)
I believe the answer is:
roo
'euro say' is the definition.
(euro is a type of common wallaroo aka roo)
'expressed regret' is the wordplay.
'expressed' shows a homophone (sound like).
'regret' becomes 'rue' ('rue' can be a synonym of 'regret').
'rue' sounds like 'ROO'.
'for' is the link.
(Other definitions for roo that I've seen before include "Hopper" , "large animal" , "Marsupial (abbrev.)" , "Kanga's son (Pooh)" , "Diminutive inhabitant of Hundred Acre Wood" .)