certain common characteristics.
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 onomatopoeia "woooooo!" as a reaction to dimmed lights or magic tricks. The term implies a lack of either intelligence or sincerity on the part of the person or concepts so described.
As a coincidence, the Chinese word "Wū" (巫
means a shaman, usually with magic powers.
Despite the terrible name, it has become quite a popular term. Woo is sometimes synonymous with bullshit, though there are differences. Bullshit is generally just a lie pulled out of wherever, about whatever. Woo is understood specifically as pseudoscience, uses a science-like formula, and attempts to place itself as scientifically, or at least reasonably, supported.
Woo generally contains most of the following characteristics:
A simple idea that purports to be the one answer to many problems (often including diseases)
A "scientific-sounding" reason for how it works, but little to no actual science behind it; for example, quote mines of studies that if bent enough could be described in such a way to support it, outright misapplication of studies, or words that sound scientific but make no sense in the context they are used in
It involves the supernatural and paranormal (not necessarily)
A claim of persecution, usually perpetrated by the government or the pharmaceutical, medical, or scientific community
An invocation of a scientific authority
Prefers to use abundant testimonials over actual scientific research
A claim that scientists are blind to the discovery, despite attempts to alert them
A disdain for objective, randomized experimental controls, especially double-blind testing (which are kind of what makes epidemiology actually, y'know, work)
And, usually, an offer to share the knowledge for a price.
http://rationalwiki.org/wiki/Woo