What is "tarring and feathering"?

Tarring and feathering was used in wars and political disagreements to humiliate groups of people with different views. A group of people would sometimes jump a person or group of people, dump tar on them and throw feathers at them. The feathers would stick to the tar and the person or people would have to walk home humiliated, covered in tar and feathers.

~Crutchie