The definition of cult: Cult means a group of people. Based on terminology cult is a group of people who are separated from the followers of a religion due to difference in theological issues and select special beliefs and explanations.
During the history of Islam, there were various cults which have been separated due to various events and phenomena. Those cults can be divided into two groups:
1) Although some cults are different in some theological issues or in explaining those issues with other Muslims and sometimes they act against other Muslims in secondary commandments; but they are united in principles. They believe in some issues such as monotheism, prophethood, resurrection and etc. and act Hajj, fasting, Alms tax and etc.
Cults such as Ahle hadith, Mo'atazeleh, Ashaereh, Mataridieh, Wahhabism and the like are of such cults…
Second group: There are some other cults which have been originated from Islam religion; but they have severed from the religion of Islam to such an extent that they aren’t in common with Muslim due to going to extremes of their leaders and followers: They have deviated the Islaimc learnings in main issues and eventually they have rejected them. For instance, some unfamiliar cults can be pointed out which are called "Qali" in cult and religion books. Some of these cults have considered their leaders as God instead of the Islamic monotheism and they have been trapped in metempsychosis instead of resurrection and have also rejected praying, fasting, hajj and etc. completely offering deviating justifications. Cults such as Ishraqieh, Horoufieh, Helmanieh and etc. are of such cults. Those cults have ben originated from Islam and are mentioned in the history of Islamic cults; but other Muslims don’t consider them as Muslims.
Regarding the above-mentioned definition of cult, it can be said that Baha'ism is one of the Islamic cults from the second group. Its first followers were Muslims and were living in Islamic lands; that is, one of the cults which has rejected Muslims' principles and secondary points and separated from Muslims. However, it should be paid attention that not only other Muslims don’t consider Baha'is as one of the Islamic cults; but also they themselves are claiming for having a new religion.
The definition of religion:
Religion is one of the superficially simple term whose comprehensive definition is impossible. There are many different and various ones offered even offering imperfect list isn’t feasible.
In the holy Quran, the word "دین" is offered in various meanings such as reward, obedience, kingdom, religious law, nation, beliefs, surrendering and etc. Various meaning have been mentioned in traditions for the word "دین"
According to the verse: "لکم دینکم ولی دین" (کافرون/6) "Unto you tour religion, and unto me my religion" [Al-Kaferoun/6], the Baha'ism creed is a religion like polytheists' one. However, according to the verse: "انَّ الدّین عندالله الاسلام..." (ال عمران/ 19)
"Lo! Religion with Allah (is) the Surrender 9to his will and guidance)… "[Al-Imran/19], the Baha'ism creed hasn’t been a religion and is separated from religion.
Also, if we pay attention to the definitions offered by western and Islamic theologians, we will conclude various results. For example, some theologians have said: "Religion is the divine rules which have been enacted in order to make the owners of wisdom achieve benevolent. According to the above-mentioned definition Baha'ism can't be considered as a religion because the investigation of history has indicated that its rules haven’t been divine and been forged by the Colonialists in order to disunite Muslims.
Some Westerns such as Emile Durkheim have defined religion as follows: "Religion is a system of beliefs and customs with regard to holy things which bond people in the form of social groups." Supposing the accepting this definition, it can be said that Baha'ism creed includes the following definition of religion because this creed is a system of beliefs and customs which has been some via a social group.
According to the above-mentioned materials it can be concluded that various definitions of cult and religion can be offered as various answers to the mentioned question.
Baha'ism is a forged creed. Although it is related to Muslims due to its origin and historical background of its founders; but it is nothing but a man-made creed like hundreds and thousands of schools and creeds due to its nature. Because the followers of this creed aren’t atheists; so they must be behaved like polytheists.