Anti-Christ
From MormonWiki
"Anyone or anything that actively opposes Jesus Christ (either openly or secretly) is an anti-Christ" (“Lesson 20: Korihor, the Anti-Christ,” Primary 4: Book of Mormon, 67)
Examples of an Anti-Christ
Korihor is an important character in the Book of Mormon whose rise and fall occurred in about 74 B.C. and whose entire story is told in Alma chapter 30. Korihor is introduced as Anti-Christ because he preached against the prophecies of the coming of Christ