Ruffian refers to someone who is tough or rowdy person. He is generally considered to have a violent nature and can be violent towards weaker people. Hence, a ruffian is often used interchangeably with bully. A ruffian often threatens and hurts other people.
The term, ruffian, is often used to refer to someone with criminal intent, or someone who commits crimes. He may even be involved in a criminal gang or association. In a gang, a ruffian usually acts as a thug or goon, who uses brute strength to intimidate someone in doing what he wants or what the gang wants.
The term ‘ruffian’ comes from the Middle French ‘rufian’, which comes from the Italian ‘ruffiano’, which means ‘pimp.’ Some words that are synonymous with ruffian are thug, scoundrel, villain, rogue, rascal, lout, hooligan, hoodlum, vandal, delinquent, rowdy, bully boy, bully, brute; etc.