Nothing but a new town (4)
I believe the answer is:
nowt
'nothing' is the definition.
(I've seen this before)
'a new town' is the wordplay.
'a new' is an anagram indicator.
'town' is an anagram of 'NOWT'.
'but' is the link.
(Other definitions for nowt that I've seen before include "Nothing (northern English)" , "Duck" , "Northern 15 [NIX]" , "Nothing (northern England dialect)" , "Nothing (N. English)" .)