Holy circle in church a lot (4)
I believe the answer is:
halo
'holy circle' is the definition.
'in church a lot' is the wordplay.
'in' indicates the answer is hidden within the clue.
'HALO' is hidden within 'church a lot'.
(Other definitions for halo that I've seen before include "Aureole" , "Ring of saintliness" , "Disc of light" , "Band of light" , "Circle painted over saint's head" .)