Siren in German legend said to lure boatmen from her rock at the edge of the Rhine (7)
I believe the answer is:
lorelei
(Other definitions for lorelei that I've seen before include "voice to die for" , "Legendary siren who lured Rhine boatmen to destruction" , "Bloody singer" , "Legendary siren and rock in the R Rhine" , "alluring female" .)