Creepy European by lake (5)
I believe the answer is:
eerie
'creepy' is the definition.
(eerie can mean strange or creepy)
'european by lake' is the wordplay.
'european' becomes 'E' (abbreviation e.g. EU).
'by' is a charade indicator (letters next to each other).
'lake' becomes 'erie' (Lake Erie is one of the Canadian/US 'Great Lakes').
'e'+'erie'='EERIE'
(Other definitions for eerie that I've seen before include "Uncannily strange" , "Mysterious" , "Unnerving" , "Spooky, creepy" , "Spine-tingling" .)