Not To Be Confused With
Docetism denies Christ's true humanity (he only appeared human); Arianism denies his true deity. The two heresies attack opposite natures of the one Christ.
From Greek dokeō, “to seem.” Often tied to Gnostic matter-hatred, docetism made the Word-made-flesh an illusion. John already aims at it: “every spirit that confesses that Jesus Christ has come in the flesh is from God” (1 John 4:2).