Time, now, to move from the built-up area (4)
I believe the answer is:
town
'the built-up area' is the definition.
(I've seen this before)
'time now to move' is the wordplay.
'time' becomes 't'.
'to move' indicates anagramming the letters.
'now' with letters rearranged gives 'own'.
't'+'own'='TOWN'
'from' is the link.
(Other definitions for town that I've seen before include "Nelson, for example" , "eg Ripley" , "Densely populated area" , "What revellers paint red" , "Community group" .)