Preacher has spoken in some obscurity (8)
I believe the answer is:
moralist
'preacher' is the definition.
(I've seen this before)
'spoken in some obscurity' is the wordplay.
'spoken' becomes 'oral' (similar in meaning).
'in' is an insertion indicator.
'some obscurity' becomes 'mist'.
'oral' inserted inside 'mist' is 'MORALIST'.
'has' is the link.
(Other definitions for moralist that I've seen before include "Person of principle" , "Ethical figure" , "Principled type" , "Ail storm (anag)" , "One teaching right and wrong" .)