Central bank supporting false medicine man (6)
I believe the answer is:
shaman
'medicine man' is the definition.
'central bank supporting false' is the wordplay.
'central' means to look at the middle letters.
'supporting' means one lot of letters go next to another (in a down clue, some letters go below others).
'false' becomes 'sham' (I've seen this before).
The centre of 'bank' is 'an'.
'an' after 'sham' is 'SHAMAN'.
(Other definitions for shaman that I've seen before include "Asian doctor-priest" , "Indian priest" , "who practises a form of spiritualism?" , "Doctor-priest working by magic" , "Sorcerer" .)