In church I mentioned ring (5)
I believe the answer is:
chime
'ring' is the definition.
(eg a bell chimes or rings)
'in church i mentioned' is the wordplay.
'in' indicates the answer is hidden within the clue.
'CHIME' can be found hidden inside 'church i mentioned'.
(Other definitions for chime that I've seen before include "Sound of bell - agree" , "Harmonise, peal" , "(Of bells) ring" , "Ring; harmonise" , "Agree (with); ring" .)