Loos' Lee (7)
I believe the answer is:
lorelei
'loos' lee' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for lorelei that I've seen before include "Jerk" , "Legendary siren who lured Rhine boatmen to destruction" , "Fatal nymph of the Rhine" , "Legendary siren and rock in the R Rhine" , "High rock in the Rhine gorge" .)