King of Judea (5)
I believe the answer is:
'king of judea' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for herod that I've seen before include "New Testament king" , "Ruler of Palestine when Jesus was born" , "child murderer" , "Christ was born in the reign of . . . . . the Great (5)" , "Royal baby-killer" .)