Church can fill emptiness, it's said (6)
I believe the answer is:
voiced
'said' is the definition.
(voicing is a kind of saying)
'church can fill emptiness' is the wordplay.
'church' becomes 'ce' (abbreviation for Church of England).
'can fill' indicates putting letters inside (I've seen this in other clues).
'emptiness' becomes 'void' ('void' can be a synonym of 'emptiness').
'ce' put into 'void' is 'VOICED'.
'it's' is the link.
(Other definitions for voiced that I've seen before include "Gave expression to, spoke" , "Said aloud" , "Sounded, uttered" , "Expressed in speech" , "Articulated" .)