Belittle church dignitary who's holding me up (6)
I believe the answer is:
demean
'belittle church' is the definition.
'demean' can be an answer for 'belittle' (belittle can mean to demean or patronise). I am unsure of the 'church' bit.
'dignitary who's holding me up' is the wordplay.
'dignitary who' becomes 'dean' (I can't justify this - if you can you should give a lot more credence to this answer).
'holding' means one lot of letters goes inside another.
'up' says the letters should be written in reverse (in down clue: letters go upwards).
'me' reversed gives 'em'.
'dean' enclosing 'em' is 'DEMEAN'.
(Other definitions for demean that I've seen before include "Debase" , "Cause to lose respect" , "make base" , "Degrade, abase" , "Lower in dignity or respect" .)