siren

Concise Oxford English Dictionary © 2008 Oxford University Press:
siren/ˈsʌɪrən/

▶noun

• 1 a device that makes a loud prolonged signal or warning sound.

• 2 Greek Mythology each of a number of women or winged creatures whose singing lured unwary sailors on to rocks.

• 3 a woman who is considered to be alluring but also dangerous in some way.

• 4 an eel-like American amphibian, typically living in muddy pools. [Family Sirenidae.]

– phrases
siren song (or call) the appeal of something that is alluring but also potentially dangerous.

– origin ME (denoting an imaginary type of snake): from OFr. sirene, from late L. Sirena, fem. of L. Siren, from Gk Seirēn.