Legendary German siren who lured boatmen to destruction (7)
I believe the answer is:
lorelei
'legendary german siren who lured boatmen to destruction' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for lorelei that I've seen before include "Rhine rock famed for siren" , "voice to die for" , "Siren of German legend who lured boatmen in the Rhine to destruction" , "Famous Rhine rock" , "A Rhine maiden" .)