Fashionable church in hollow is dirty (8)
I believe the answer is:
indecent
'is dirty' is the definition.
(associated in meaning)
'fashionable church in hollow' is the wordplay.
'fashionable' becomes 'in' (in can mean fashionable or trendy).
'church' becomes 'CE' (Church of England).
'in' indicates putting letters inside.
'hollow' becomes 'dent' (both can mean an impression or indentation).
'ce' placed inside 'dent' is 'decent'.
'in'+'decent'='INDECENT'
(Other definitions for indecent that I've seen before include "Smutty" , "Indecorous" , "Immodest or obscene" , "Gross, unbecoming" , "Vulgar" .)