1780, "mud, muddy land," from Irish slab "mud, mire dirt," itself probably borrowed from English slab "muddy place" (c. 1600), from a Scandinavian source (compare Icelandic slabb "sludge"). The meaning "untidy person" is first recorded 1887, from earlier expressions such as slob of a man (1861).[slob etymology, slob origin, 英语词源]