When a mean and nasty woman (a witch) is being mean and nasty to someone else. These kind of witches don't have cauldrons or brooms; they are just people you want to stay miles away from. Refers to a single person, not a group.
A slight offset of the term "stupid bitch" sounding more appeasing to the ear. Ones face can also become sloopy, as if their face is drooping down & their eyeballs seem to fall off their face.
"Get over here you sloopy witch!"
"The man who's face was ripped off by chimpanzees, he now looks like a sloopy witch."