Norse god of thunder (4)
I believe the answer is:
thor
'norse god of thunder' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for thor that I've seen before include "The Thunderer" , "Thursday is named after this Scandinavian god" , "Divine figure" , "Germanic thunder god; early US IRBM" , "Norse god of war" .)