Eastern lake is creepy (5)
I believe the answer is:
eerie
'creepy' is the definition.
(eerie can mean strange or creepy)
'eastern lake' is the wordplay.
'eastern' becomes 'e'.
'lake' becomes 'erie' (Lake Erie is one of the Canadian/US 'Great Lakes').
'e'+'erie'='EERIE'
'is' is the link.
(Other definitions for eerie that I've seen before include "Spooky, macabre" , "Sinister" , "Spectral" , "Strange and disturbing" , "Weird and disturbing" .)