Large church must entertain current senior politician (8)
I believe the answer is:
minister
'senior politician' is the definition.
(I've seen this before)
'large church must entertain current' is the wordplay.
'large church' becomes 'minster' (I've seen this before).
'must entertain' is an insertion indicator.
'current' becomes 'i' (symbol for electric current).
'minster' going around 'i' is 'MINISTER'.
(Other definitions for minister that I've seen before include "Member of the clergy or of the Front Bench" , "Parson" , "Agent" , "Merit sin (anag.)" , "Member of parliament" .)