Fix a sort of gate outside church (6)
I believe the answer is:
anchor
'fix' is the definition.
(anchoring is a kind of fixing)
'a sort of gate outside church' is the wordplay.
'a' becomes 'an'.
'sort of gate' becomes 'or'.
'outside' means one lot of letters goes inside another.
'church' becomes 'ch' (common abbreviation).
'an'+'or'='anor'
'anor' placed around 'ch' is 'ANCHOR'.
(Other definitions for anchor that I've seen before include "Stabilising factor" , "Horse-breeding farm" , "Fix securely" , "Mooring implement" , "Brake for a boat" .)