Mudsill

n. 1. The lowest sill of a structure, usually embedded in the soil; the lowest timber of a house; also, that sill or timber of a bridge which is laid at the bottom of the water. See Sill. [ 1913 Webster ]

2. Fig.: A person of the lowest stratum of society; -- a term of opprobrium or contempt. [ Southern U. S. ] [ Webster 1913 Suppl. ]