Archdeacon in cathedral city regularly (6)
I believe the answer is:
evenly
'regularly' is the definition.
(synonyms)
'archdeacon in cathedral city' is the wordplay.
'archdeacon' becomes 'ven' (abbreviation for The Venerable).
'in' is an insertion indicator.
'cathedral city' becomes 'Ely' (English city with a cathedral).
'ven' put into 'ely' is 'EVENLY'.
(Other definitions for evenly that I've seen before include "Smoothly, uniformly" , "Smoothly or fairly" , "(Spread) without irregularities" , "In equal proportion" , "in regular fashion" .)