Some boatmen or seafarers from Scandinavia (5)
I believe the answer is:
norse
'from scandinavia' is the definition.
(I've seen this in another clue)
'some boatmen or seafarers' is the wordplay.
'some' says the answer is hidden in the clue (some parts of the word are used).
'NORSE' is hidden in the letters of 'boatmen or seafarers'.
(Other definitions for norse that I've seen before include "Viking" , "Old Scandinavian language" , "Relating to ancient Scandinavian" , "Relating to Norway" , "Ancient Scandinavian language" .)