A Samaritan signified to the Jews as much as an impostor, or seducer; for the Jews looked upon the Samaritans as a detestable sort of men, who had corrupted the worship of God with their horrible superstitions in Mount Gerizim. And hast a devil; that is, art mad: See Poole on "1 Thessalonians 7:20".
Related Commentaries of John 8:48
John 8:48
48 Then answered the Jews, and said unto him, Say we not well that thou art a Samaritan, and hast a devil?