One with light going around southern Manhattan? (6)
I believe the answer is:
island
'manhattan?' is the definition.
(I've seen this in another clue)
'one with light going around southern' is the wordplay.
'one' becomes 'I' (Roman numeral).
'with' is a charade indicator (letters next to each other).
'light' becomes 'land' (light can mean to settle or land).
'going around' is an insertion indicator.
'southern' becomes 's' (abbreviation).
'i'+'land'='iland'
'iland' placed around 's' is 'ISLAND'.
(Other definitions for island that I've seen before include "Part of an archipelago" , "eg Rhode, Rhodes" , "Barbados, say" , "Piece of land surrounded by water" , "place of 1d [ADVENTURE]" .)