Norse thunder god (4)
I believe the answer is:
thor
'norse thunder god' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for thor that I've seen before include "Scandinavian thunder-god" , "Norse god of thunder - a weekday is named after him" , "Norse deity" , "Germanic deity" , "Germanic thunder god; early US IRBM" .)