A cult is a group which is typically led by a charismatic and self-appointed leader, who tightly controls its members, requiring unwavering devotion to a set of beliefs and practices which are considered deviant. It is in most contexts a pejorative term, also used for a new religious movement or other social group which is defined by its unusual religious, spiritual, or philosophical beliefs and rituals, or its common interest in a particular person, object, or goal. This sense of the term is weakly defined – having divergent definitions both in popular culture and academia – and has also been an ongoing source of contention among scholars across several fields of study.

A new religious movement (NRM), also known as alternative spirituality or a new religion, is a religious or spiritual group that has modern origins and is peripheral to its society's dominant religious culture. NRMs can be novel in origin or they can be part of a wider religion, in which case they are distinct from pre-existing denominations. Some NRMs deal with the challenges that the modernizing world poses to them by embracing individualism, while other NRMs deal with them by embracing tightly knit collective means. Scholars have estimated that NRMs number in the tens of thousands worldwide. Most NRMs only have a few members, some of them have thousands of members, and a few of them have more than a million members.