Is Paganism a Cult?

No, Paganism is a major World Religion, with many branches. More people on Earth are Pagans than any other faith. Some Pagan groups may be classified as cults, just like some Christian groups are cults.
The Christian groups headed by Jim Jones at Jonestown, who committed mass suicide, and the followers of David Koresh at Waco, Texas are both considered cults, but they were also Christian denominations.

Any religious or spiritual tradition can have cults in its midst, that does not mean that the entire tradition is a cult. Wackos and religious charletans come in all religions, denominations, and races.

The word Cult is often used as a slur word to disparage someone elses religious beliefs. It is frequently used derisively toward non-white or indigenous folk cultures and their beliefs.

Paganism (from Latin paganus, meaning "country dweller", "rustic") is a blanket term typically used to refer to religious traditions which are polytheistic or indigenous.

It is primarily used in a historical context, Greco-Roman polytheism as well as the polytheistic traditions of Europe and North Africa before Christianization. In a wider sense, extended to contemporary religions, it includes most of the Eastern religions and the indigenous traditions of the Americas, Central Asia, Australia and Africa; as well as non-Abrahamic folk religion in general. More narrow definitions will not include any of the world religions and restrict the term to local or rural currents not organized as civil religions. Characteristic of Pagan traditions is the absence of proselytism and the presence of a living mythology, which informs religious practice.

Ethnologists often avoid the term "pagan," with its uncertain and varied meanings, in referring to traditional or historic faiths, preferring more precise categories such as polytheism, shamanism, pantheism, or animism.

In the late 20th century, "Paganism", or more correctly "Neopaganism", became widely used in reference to adherents of various new religious movement including Wicca. As such, various modern scholars have begun to apply the term to three groups of separate faiths: Historical Polytheism (such as Celtic polytheism, Norse Paganism, the Cultus Deorum Romanorum and Hellenic Polytheistic Reconstructionism also called Hellenismos), Folk/ethnic/Indigenous religions (such as Chinese folk religion and African traditional religion), and Neopaganism (such as Wicca and Neo-Druidism).