noun seductress, siren, charmer, vamp (informal), Circe, enchantress the allure of the femme fatale

a femme fatale (pron.: /ˌfɛm fəˈtæl/ or /ˌfɛm fəˈtɑːl/; French: [fam fatal]) is a mysterious and seductive woman  whose charms ensnare her lovers in bonds of irresistible desire, often leading them into compromising, dangerous, and deadly situations. She is an archetype of literature and art. Her ability to entrance and hypnotise her victim with a spell was in the earliest stories seen as being literally supernatural; she, the femme fatale today is still often described as having a power akin to an enchantress, seductress, vampire, witch, or demon, having some power over men.

The phrase is French for "deadly woman". A femme fatale tries to achieve her hidden purpose by using feminine wiles such as beauty, charm, and sexual allure. In some situations, she uses lying or coercion rather than charm. She may also make use of some subduing weapon such as sleeping gas, a modern analog of magical powers in older tales. She may also be (or imply that she is) a victim, caught in a situation from which she cannot escape; The Lady from Shanghai (a 1947 film noir) is one such example. A younger version of a femme fatale would be called a fille fatale, or "deadly girl."

Although typically villainous, if not morally ambiguous, and always associated with a sense of mystification and unease, femmes fatales have also appeared as antiheroines in some stories, and some even repent and become true heroines by the end of the tale. Some stories even feature benevolent and heroic femmes fatales who use their wiles to snare the villain for the greater good. In social life, a more malevolent femme fatale tends to torture her lover in an asymmetrical relationship, denying confirmation of her affection. She usually drives him to the point of obsession and exhaustion, so that he is incapable of making rational decisions...