Blackguard

(bläg'gärd), n. [It originally meant the guard of the devil; thence, a fit attendant on the devil, and then a dirty fellow of the meanest kind. Stanihurst's Descript. of Ireland: “They are taken for no better than rakehells, or the devil's blacke guarde.” Fuller's Holy War: “A lamentable case, that the devil's black guard should be God's soldiers.” Howard's Defens., 1583: “The devil and his blacke guard.”]

1. Originally, the scullions and lower menials of a court, who, in a removal from one residence to another, had charge of the kitchen utensils, &c., and being smutted by them, were jocularly called the “black guard.” “Next unto whom goeth the black guard and kitchenry.” Holland. “A lousy slave, that rode with the black guard in the duke's carriage, 'mongst spits and dripping-pans.” Webster. “One o' the black guard had his hand in my vestry.” B. Jonson.
2. Hence, a person of low character, accustomed to use scurrilous language, or to treat others with foul abuse.