Religious skeptic (8)
I believe the answer is:
agnostic
'religious skeptic' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for agnostic that I've seen before include "Coasting with unbeliever" , "Questioning" , "He doesn't believe" , "someone like Pyrrho" , "He finds it difficult to believe" .)