"Woo" is shorthand for "woo woo" and is not just limited to alternative medicine but rather represents an entire philosophy of credulity of the sort favored by New Age types. It's clear that "woo" or "woo woo" can refer to either a person or a belief system. When it refers to the person, it is referring to a person who believes in woo. To me, when referring to "alternative medicine," I view the "altie" and "woo" as largely synonymous, but woo has a broader meaning, embracing a wider variety of credulity. One thing is for sure, it is not generally meant as a flattering term--for very good reason
So what is woo Eric?
If I had to boil it down, I'd define woo as beliefs that clearly demonstrate magical thinking, uncritical acceptance of things for which no good evidence exists. This includes, but is not limited to, psychic phenomenon, ghosts, the paranormal, "energy healing," the use of "colon cleansing" and "liver cleansing" to rid oneself of "toxins," homeopathy (especially quantum homeopathy), and a wide variety of other mystical and pseudoscientific beliefs. Woo is resistant to reason. Indeed, woo has a double standard when it comes to what it considers to be good evidence. It is very accepting of a wide variety of fuzzy, mystical ideas, but is often incredibly distrustful and skeptical of anything having to do with "conventional" science or "conventional" medicine. Woos tend to be very quick to react to defend their particular brand of woo and very unforgiving of its being questioned. We have web sites just for woo bashing, And I have speed dialing so I don't wing the wong number.
,That my eight cents worth.