One must be careful to distinguish between the sociological position of what constitutes a cult (i.e., which states that whatever is normative to a given culture is not cultic) and the theological position (i.e., which states that only those groups that adhere to the Bible as the basis for all theology and practice are considered normative, and thereby, not cultic).
From the theological viewpoint, any group or religious system, whether it calls itself "Christian" or not, that offers other criteria as equal to or superior to the Bible, including but not limited to erroneous and/or exclusive interpretations of Scripture, should be considered a cult. From the theological position, then, a cult can be best defined as:
A system of religious beliefs and rituals with a body of adherents deeply devoted to an extrabiblical person, idea, or thing; it cultivates worship in a religion that, with reference to its basis for man's salvation, is considered to be unorthodox, spurious, or false, thereby insulating its members against true salvation in Christ. And inasmuch as the central doctrine of Biblical Christianity is the sacrificial death of Christ for man's sin (Eph. 2:8,9), all cultic deviations tend to downplay the finished work of Christ and emphasize the importance of earning moral acceptance before God through one's own religious works. ..... more information
The New Age Movement (NAM) is both a religious and a social movement. In fact, Western culture is currently experiencing a phenomenal, spiritual, ideological, and sociological shift. It is a religious world view that is alien and hostile to Christianity. It's a multi-focused, multi-faceted synthesis, in varying degrees, of the Far Eastern, mystical religions, mainly Hinduism, Buddhism, Taoism, and Western Occultism, adapted to and influenced by Western, materialistic culture. It sometimes appears in secularized forms. ..... more information