According to author Gregory Maguire, the name of
the Wicked Witch of the West, tragic antiheroine of The Wizard of Oz. From the initials of Oz author L. Frank Baum: eLFaBa.
Also the "title" character of the musical Wicked, based on
Maguire's book Wicked: The Life and Times of the Wicked Witch of the West.
Used as an epithet for one whose actions are cold-hearted (as in the classic view of a
wicked witch), or used sarcastically when one's actions are misguidedly noble or terroristic in nature. (In Maguire's book, Elphaba spent several years as part of a terrorist group fighting the injustices the Wizard caused for the people and Animals of Oz.)
Example of sarcastic use in response to miguidedly noble intent:
Irate Urbandictionary Editor:
This is ridiculous. How do all these crap definitions get through?! I'm going to freaking hack this site and delete all the crap ones.
Annoyed, but Slightly Calmer Editor:
Whatever you say, Elphaba.