Boat from south Jersey or Guernsey? (4)
I believe the answer is:
scow
'boat' is the definition.
(scow is a kind of boat)
'south jersey or guernsey?' is the wordplay.
'south' becomes 's' ('S' can be a synonym of 'south').
'jersey or guernsey?' becomes 'cow' (two types of cow).
's'+'cow'='SCOW'
'from' acts as a link.
(Other definitions for scow that I've seen before include "Unpowered freight barge" , "Wide-beamed dinghy" , "ighter" , "Low boat" , "Maybe lighter" .)