Tarred imp. & p. p. : of Tar

Example:
What does 'Tarred' mean in the below sentence and what does 'shill' mean? Is 'shill' a verb here?

Taxonomy
tarred and feathered, tarring and feathering, punishment, mob, victims, tar and feathers, episode, free encyclopedia, Customs service, tar and feather, attack, the practice, British soldiers, Madrid, friars, bodies, harbor, treatment.

Defination from the web:
tarred and feathered a Swiss-born Jesuit priest, Father John Bapst, in the ... Edgar Allan Poe's humorous short story "The System of Doctor Tarr and Professor Fether" features the staff of an insane asylum being tarred and feathered. ...