Declaration from nun meant no ill outside church (12)
I believe the answer is:
announcement
'declaration' is the definition.
(announcement is a kind of declaration)
'nun meant no ill outside church' is the wordplay.
'ill' is an anagram indicator.
'outside' is an insertion indicator.
'church' becomes 'CE' (abbreviation for Church of England).
'nun'+'meant'+'no'='nunmeantno'
'nunmeantno' with letters rearranged gives 'announment'.
'announment' placed around 'ce' is 'ANNOUNCEMENT'.
'from' is the link.
(Other definitions for announcement that I've seen before include "Public notice" , "Proclamation" , "A public statement" , "report" , "Statement, declaration" .)