Deianeira or Deianira was
Herakles's second wife (post madness and Twelve Labours).
Herakles is better known by his
Roman name,
Hercules. You can read more about her on Wikipedia:
http://snipurl.com/ach5.
As for the name's meaning, Oxygen.com has the name listed as Deyanira. They say it's used in Spanish and means "forceful killer" in Greek (
http://snipurl.com/achl). Deyanira may be the Spanish form of the name. Usually Oxygen's fairly reliable, but here the meaning's a touch suspect to me. Since Deianira accidentally killed her
Herakles, it seems a little too coincidental that her name should mean "killer". (Similarly, some say
Hera means "queen", when it doesn't; they're mistakenly using
Hera's title as her name's meaning.) But I could be wrong, and am quite willing to be contradicted.
Miranda