European to snore terribly (5)
I believe the answer is:
norse
'european' is the definition.
(I know that Norse is a type of european)
'snore terribly' is the wordplay.
'terribly' indicates anagramming the letters.
'snore' with letters rearranged gives 'NORSE'.
'to' is the link.
(Other definitions for norse that I've seen before include "Old European" , "Old Scandinavian tongue" , "Language - senor! (anag)" , "Ancient Scandinavian language" , "Relating to ancient Scandinavia" .)