The word Paganism has various meanings. For many Christians it is a derogatory word for any religion which is not Abrahamic, this corresponds to the Islamic concept of Kafir. Others see Paganism as synonymous with Polytheism. Well known Pagan religions are, the Greco Roman religion, the Celtic religion and the Nordic religion now known as Asatru. Pagan movements like Wicca blend these and other religious traditions.
See New Age-ism.