Woo-woo

The term woo-woo is an informal noun or adjective associated with pseudoscientific phenomena.

When used to describe an idea or theory, it means one which is unsubstantiated or easily disproven.

When used to describe a person, it means someone who believes radical non-conventional ideas without any solid foundation or scientific evidence. It is often interpreted as an insult, although it is not always intended as such.