mudsill

noun

1. The lowest sill of a structure, usually placed in or on the ground.
2. (figuratively)A particularly low or dirty place/state; the nadir of something (see rock bottom)

   “The Pre-Historic Era was the mudsill of human development.”

3. (Southern-US, dated)A person of low status or humble provenance.

   “1861, Theodore Winthrop, Washington as a Camp, The Following Is the Oath We were now miserable mercenaries, serving for low pay and rough rations. Read the Southern papers and you will see us described. “Mudsills,” — that, I believe, is the technical word.”

   “General Lee throw down his sword and surrender his invincible Southern legions to that poor little Northern mud-sill, a late tanner from Illinois!”

   “Though the mudsill of the labor world, he whistles as he hoes, and no dark broodings or whispered conspirings mar the cheerful acceptance of the load he bears.”