A man whose manners and sentiments are decidedly below those of his class deserves to be called a blackguard.
1899, Knut Hamsun, Hunger, translated by George Egerton, Part I, page 68
Pawn another man's property for the sake of a meal, eat and drink one's self to perdition, brand one's soul with the first little sear, set the first black mark against one's honour, call one's self a blackguard to one's own face, and needs must cast one's eyes down before one's self? Never! never!