A ruffian is a bully, someone who is violent toward others. Maybe they had a bad childhood, or perhaps they like the sound of people in pain. No matter where they come from, ruffians are best avoided.
Soccer fans have a reputation for being ruffians. Sure, some are sensitive poetry-reading types, but the ones that get the most attention scream obscenities, break things, and fight each other. Ruffian comes from a Germanic word that literally translates as “scabbiness,” and perhaps ruffians are covered in scabs from all the fights they start. Sometimes a ruffian is a person involved in crime, however, the word is always used to describe someone who’s a cruel, violent jerk.