Meaning: a Greek feminine name meaning "man-destroyer" or "destroyer of her husband" from Greek elements deioo (to destroy) and aner (man).
In Greek mythology Deianera is the second wife of the hero and demi-god Heracles. The daughter of Oeneus, king of Calydon, she was nearly abducted by a centaur named Nessus who attempted to rape her, though she was saved by Heracles who shot him with a poisoned arrow. As he was dying, Nessus managed to persuade Deianeira that if she took some of his blood and made it into a potion, it would ensure that Heracles would be faithful to her. For whatever reason she believed him, and kept it until Heracles fell in love with Iole, which was when she sprinkled it on his shirt. However, it turns out the centaur's blood is toxic to Heracles and it burns him terribly, driving him mad until he throws himself on a funeral pyre. Deianeira kills herself afterward in despair.
There's also another Deianeira in Greek mythology, an amazon who was (ironically) killed by Heracles during his quest for the girdle of Hippolyta.