Powerful attraction (9)
'powerful attraction' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for allure that I've seen before include "Enticement, attraction" , "Entice or attract - sounds like a decoy" , "Powerful fascination" , "Attractiveness, glamour" , "Tempt" .)
(Other definitions for magnetism that I've seen before include "Attractive force" , "Drawing power" , "Charisma" , "Attraction" .)