Remainer's regret about answer given in public? (8)
I believe the answer is:
european
'remainer's' is the definition.
I can't judge whether this defines the answer.
'regret about answer given in public?' is the wordplay.
'regret' becomes 'rue' (to rue something is to regret it).
'about' says the letters should be written in reverse.
'answer' becomes 'a' (abbreviation eg in Q and A).
'given in' is an insertion indicator.
'public?' becomes 'open' ('open' can be similar in meaning to 'public').
'rue' backwards is 'eur'.
'a' placed into 'open' is 'opean'.
'eur'+'opean'='EUROPEAN'
Can you help me to learn more?
(Other definitions for european that I've seen before include "Continental is curiously A-one pure" , "Relating to the continent" , "The continental is a pure one" , "Pole, perhaps" , "Swede, perhaps?" .)