Blackmail, the crime of obtaining or attempting to obtain money or property by unlawful threats or intimidation. Blackmail also means the money or property collected by these means. The blackmailer threatens to accuse the other person of having committed a crime, to injure him or his family, to damage his property, or to expose him to shame or public disgrace.
Originally, blackmail probably referred to rent paid in work, grain, or base coin rather than in silver, or white, money. Later, blackmail meant the money, or tribute, paid to robbers by persons living along the Scottish border to protect themselves from raids. This practice lasted until the early 17th century.