Exceptionally valiant north European (7)
I believe the answer is:
latvian
'north european' is the definition.
(Latvia is in northern Europe)
'exceptionally valiant' is the wordplay.
'exceptionally' indicates anagramming the letters.
'valiant' with letters rearranged gives 'LATVIAN'.
(Other definitions for latvian that I've seen before include "From one Baltic state" , "Baltic language" , "republican" , "Nationality of citizen of Riga" , "European national" .)