Staff supporting that man, biblical ruler (5)
I believe the answer is:
herod
'biblical ruler' is the definition.
(I've seen this in another clue)
'staff supporting that man' is the wordplay.
'staff' becomes 'rod' (both can mean a stick or cane).
'supporting' says to put letters next to each other (in a down clue, some letters go below others).
'that man' becomes 'he' (pronoun for a man).
'rod' after 'he' is 'HEROD'.
(Other definitions for herod that I've seen before include "New Testament king" , "Old king" , "King of Judea who ordered the death of children under two in Bethlehem" , "King of Judaea, temple builder" , "NT king" .)