Jamieson, Fausset and Brown on Daniel 11:21

21. vile--Antiochus called Epiphanes, that is, "the illustrious," for vindicating the claims of the royal line against Heliodorus, was nicknamed, by a play of sounds, Epimanes, that is, "the madman," for his mad freaks beneath the dignity of a king. He would carouse with the lowest of the people, bathe with them in the public baths, and foolishly jest and throw stones at passers-by [Polybius, 26.10]. Hence, as also for his crafty supplanting of Demetrius, the rightful heir, from the throne, he is termed "vile."

they shall not give ... kingdom: but ... by flatteries--The nation shall not, by a public act, confer the kingdom on him, but he shall obtain it by artifice, "flattering" Eumenes and Attalus of Pergamos to help him, and, as he had seen candidates at Rome doing, canvassing the Syrian people high and low, one by one, with embraces [Livy, 41.20].