Just impediment, see (6)
I believe the answer is:
barely
'just' is the definition.
(synonyms)
'impediment see' is the wordplay.
'impediment' becomes 'bar' (bar is a kind of impediment).
'see' becomes 'ely' (see is a place with a cathedral - e.g. Ely).
'bar'+'ely'='BARELY'
(Other definitions for barely that I've seen before include "By a small margin" , "as Godiva rode?" , "how naturists exist" , "Just about, nothing to spare" , "Not quite" .)