Joseph Laycock endorses a dubious academic habit in Defining "Cult," Defining "Christian" Religion Dispatches 10/12/2011, of refusing to use the word "cult" to describe cult group. Academics tend to prefer the term "new religious movements". Referring to the concept of cult, Laycock writes, "This term is never defined in a coherent way."
Actually, defining cults may be a challenge, but it's far from impossible. A number of countries define cults by law, including Germany and Austria. And scholars like Janja Lalich, Michael Langone and the late Margaret Thaler Singer have done quite a good job of defining cults in scholarly terms. The International Cultic Studies Association (ICSA) provides continuing research on cults, including their annual International Journal of Cultic Studies.