1550s, second element is M.E. male "rent, tribute," from O.E. mal "lawsuit, terms, bargaining, agreement," from O.N. mal "speech, agreement;" related to O.E. mæðel "meeting, council," mæl "speech," Goth. maþl "meeting place," from P.Gmc. *mathla-, from PIE *mod- "to meet, assemble." From the practice of freebooting clan chieftains who ran protection rackets against Scottish farmers. Black from the evil of the practice. Expanded c.1826 to any type of extortion money. Verb is 1880.