Not all witches are created equal. There are ugly evil witches, beautiful good witches, and many variations in between. Some people think that there isn't really any such thing as a witch or witchcraft, while others believe that it's very real. The Abrahamic religions of Judaism, Christianity and Islam consider witchcraft to be evil. They see it as incompatible with belief in Yahweh, God or Allah.
In medieval Europe, anything that wasn't understood was attributed to magic or witchcraft. People thought that witches had made a pact with the Devil that let them cause illness or influence the weather or see the future. Of course, in that era nobody understood how infectious diseases spread or how the weather worked. So any misfortune must be either a punishment from God, or else the result of witchcraft by a person under the Devil's influence. Anybody who was different in some way, or didn't attend church, or had offended someone could be accused of witchcraft. Illnesses that in the 21st century we call epilepsy or schizophrenia, in the 14th century were evidence of sorcery. The sorcery could be performed either by the afflicted person or by some other person. Every student of American history has heard of the infamous Salem witch trials of 1692 and 1693. They resulted in the execution of 20 accused "witches."
Modern fictional portrayals of witchcraft have been more sympathetic, as in J.K. Rowling's Harry Potter books. Glinda, the Good Witch in The Wizard Of Oz, is another example. Our witch costumes run a wide gamut. At one end of the spectrum we have the "classic" image of a long black dress and cone-shaped hat. At the other, cute, colorful and whimsical ensembles that suggest white magic. And of course, we have a full range of licensed Wizard of Oz and Harry Potter costumes. We have everything you need to concoct a magical masquerade!