A ruffian is a man who behaves violently and is involved in crime.
例句
...gangs of ruffians who lurk about intent on troublemaking.潜伏在周围意图制造麻烦的匪帮
英汉词典释义
n.
暴徒, 恶棍
Some local ruffians are responsible for this.某些当地歹徒应负此责。The ruffian threatened to run his victim through if he did not hand over all his money.暴徒恐吓受害者说如果他不把所有的钱都交出来,就捅死他。