(noun)
in Greek mythology, a winged creature partially resembling a human woman, known to have a singing voice that could lure sailors to be destroyed by the rocks;
e.g. The painting depicts a siren sitting on a rock with a ship sailing past.
(noun)
broadly, a woman who is seen as being fascinating and tempting in some way, but also dangerous for some reason;
e.g. They didn't trust that a siren like her would have their wellbeing at heart.
(adjective)
tempting, attractive, or inviting in some way, especially despite being harmful (often used as "siren song" or "siren call");
e.g. They were influenced by the siren call of an exotic new destination.