Minister is nosy — start of trouble (6)
I believe the answer is:
priest
'minister' is the definition.
(a church minister)
'is nosy start of trouble' is the wordplay.
'is nosy' becomes 'pries' (I've seen this in another clue).
'start of' says to take the initial letters.
The initial letter of 'trouble' is 't'.
'pries'+'t'='PRIEST'
(Other definitions for priest that I've seen before include "Art looking into" , "Religious official" , "Spiritual leader" , "stunner" , "Church minister" .)