Sucker turned to Russia's foremost spiritual adviser (6)
I believe the answer is:
pastor
'spiritual adviser' is the definition.
The answer and definition can be both people as well as being singular nouns.
Maybe you can see a link between them that I don't see?
'sucker turned to russia's foremost' is the wordplay.
'sucker' becomes 'sap' (I've seen this before).
'turned' shows that the letters should be reversed in order.
'foremost' says to take the initial letters.
The first letter of 'russias' is 'r'.
'sap' in reverse letter order is 'pas'.
'pas'+'to'+'r'='PASTOR'
Can you help me to learn more?
(Other definitions for pastor that I've seen before include "One with a flock (of people)" , "Churchman" , "Flock's leader" , "Minister; shepherd" , "Minister of religion" .)