Skeptics' jargon. "The term comes from "woo-woo", an epithet used in the 1990s by science and skeptical writers to ridicule people who believe or promote such things. This is in turn believed to have come from the use of "woooooo!" as a reaction to dimmed lights or magic tricks, and generally implies a lack of either intelligence or sincerity on the part of the person or concepts so described." - supposedly.