This comes from the Norwegian word troll, which refers to a Scandinavian mythological monster. In the context of social media and digital forums, these are robots or people that make negative or offensive comments, which create debates, instigate, upset, or insult. Often they use false identities.
When they attack feminists people or content, or that defend women’s rights or collectives of sexual and gender diversity, they are referred to as sexist trolls.