Creepy-sounding lake (4)
I believe the answer is:
erie
'creepy-sounding lake' is the definition.
(I've seen this in another clue)
'sounding lake' is the wordplay.
'sounding' shows a homophone (sound like).
'lake' becomes 'eerie'.
'eerie' is a homophone of 'ERIE'.
(Other definitions for erie that I've seen before include "North american lake sounds spooky" , "One of the Great Lakes" , "Buffalo's lake" , "A Great American lake - sounds spooky" , "Great lake in Eire" .)