Ghostly eastern lake (5)
I believe the answer is:
eerie
'ghostly' is the definition.
(eerie means odd or strange)
'eastern lake' is the wordplay.
'eastern' becomes 'e'.
'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 "Awesome" , "Weird and disturbing" , "Strangely frightening" , "Strange, unusual" , "Unnerving" .)