Cunning church following a Republican (4)
I believe the answer is:
arch
'cunning' is the definition.
(I've seen this before)
'church following a republican' is the wordplay.
'church' becomes 'ch' (common abbreviation).
'following' is a charade indicator (letters next to each other).
'republican' becomes 'r' (abbreviation).
'a'+'r'='ar'
'ch' put after 'ar' is 'ARCH'.
(Other definitions for arch that I've seen before include "Affectedly playful (4)" , "Curved part of stone bridge, perhaps" , "Prefix meaning cheif, perhaps enemy" , "Cunning; span" , "Chief: crafty" .)