Southernmost Great Lake (4)
I believe the answer is:
erie
'southernmost great lake' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for erie that I've seen before include "Spooky-sounding" , "Superior companion" , "One of the Great Lakes" , "North american lake sounds spooky" , "N. American lake" .)