Old Scandinavian tongue (5)
I believe the answer is:
norse
'old scandinavian tongue' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for norse that I've seen before include "Ancient Scandinavian language" , "Of old Scandinavia" , "Old European" , "Relating to ancient Scandinavian" , "Old Scandinavian tongue" .)