Frustrated Caledonian goes to church with editor (8)
I believe the answer is:
scotched
'frustrated' is the definition.
('scotch' can be a synonym of 'frustrate')
'caledonian goes to church with editor' is the wordplay.
'caledonian' becomes 'Scot' (Caledonia was the Latin name for Scotland).
'goes to' means one lot of letters go next to another.
'church' becomes 'ch' (common abbreviation).
'with' is a charade indicator (letters next to each other).
'editor' becomes 'ed' (abbreviation).
'scot'+'ch'+'ed'='SCOTCHED'
(Other definitions for scotched that I've seen before include "Frustrated" , "Put the lid on" .)