Demon not spreading capital (8)
I believe the answer is:
edmonton
'capital' is the definition.
(Edmonton is an example)
'demon not spreading' is the wordplay.
'spreading' indicates anagramming the letters.
'demon'+'not'='demonnot'
'demonnot' anagrammed gives 'EDMONTON'.
(Other definitions for edmonton that I've seen before include "destination for Gilpin" , "Part of London (or Alberta)" , "Tom Donne is out in the Canadian city" , "Canadian city - region of London" , "Canadian provincial capital" .)