1950, with -ism + name of U.S. Sen. Joseph R. McCarthy (1908-1957), leader of U.S. anti-Communist agitation. The term is said to have been coined by "Washington Post" political cartoonist Herbert Block ("Herblock"). The surname is from Irish Mac Carthaigh "son of Carthach" (Welsh Caradawc), an ancient Celtic name, also known in its Latinized form, Caractacus (last of the British leaders to resist Rome, captured 51 C.E.)