Proselytism

Proselytism is the practice of attempting to convert people to another opinion and, particularly, another religion. 
The word "proselytism" comes from the Greek language prefix 'pros' (towards) and the verb 'erchomai' (I come). Historically in the New Testament, the word proselyte meant a person who had converted to the Jewish religion. Though the word proselytism was originally used in Christianity, it is also used to refer to other religions' attempts to convert people to their beliefs or even any attempt to convert people to another point of view, religious or not. Today, the connotations of the word proselytism are often negative.