Norse god of wisdom and war (4)
I believe the answer is:
odin
'norse god of wisdom and war' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for odin that I've seen before include "Supreme god of war in Norse mythology" , "an all-powerful one" , "King of Norse gods" , "Legendary ruler" , "The supreme Norse god and creator" .)