Border south of duke's abode (5)
I believe the answer is:
dwelt
'abode' is the definition.
(historical past tense form of 'abide')
'border south of duke's' is the wordplay.
'border' becomes 'welt' (type of border on a garment).
'south of' is a charade indicator (letters next to each other).
'duke' becomes 'd'.
'welt' put after 'd' is 'DWELT'.
(Other definitions for dwelt that I've seen before include "I dreamt I . . . in marble halls (song)" , "Lived, resided" , "Thought moodily (about something)" , "Remained" , "Stayed" .)