Steadfast belief (5)
I believe the answer is:
dogma
'steadfast belief' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for dogma that I've seen before include "Blind faith required" , "Doctrine laid down with authority" , "Belief, precept" , "Doctrine accepted as true without proof" , "Inflexible principles" .)