Support of faithful crumbling (7)
I believe the answer is:
fulcrum
'support' is the definition.
(thesaurus)
'of faithful crumbling' is the wordplay.
'of' indicates the answer is hidden within the clue.
'FULCRUM' can be found hidden inside 'faithful crumbling'.
(Other definitions for fulcrum that I've seen before include "place to get a purchase!" , "prop" , "Pivot on which a lever moves" , "Pivot about which a lever turns" , "The point on which a lever turns" .)