"Against Christ, or an opposition Christ, a rival Christ. The" word is used only by the apostle John. Referring to false "teachers, he says (1 John 2:18, 22; 4:3; 2 John 1:7), "Even now" "are there many antichrists." "(1.) This name has been applied to the "little horn" of the "king of fierce countenance (Dan. 7:24, 25; 8:23-25)." "(2.) It has been applied also to the "false Christs" spoken of "by our Lord (Matt. 24:5, 23, 24)." "(3.) To the "man of sin" described by Paul (2 Thess. 2:3, 4, 8-10). "(4.) And to the "beast from the sea" (Rev. 13:1; 17:1-18).

See where Antichrist occurs in the Bible...

Definition of Antichrist:
"an adversary to Christ"