motherfucker (n.)

also mother-fucker, by 1956, usually simply an intensive of fucker. It is implied in clipped form mother (with the context made clear) by 1928; motherfucking is by 1906. Abbreviation m.f. (for motherfucking) is in a rendition of soldier talk in Pound's "Pisan Cantos" (1948).

A short time after he returned, appellant drew a six-shooter and told deceased, in a loud tone of voice, that he would shoot his God damn heart out, and called him a mother-fucking son of a bitch. He held his pistol on him a little while, and then put it in his pocket, and stood there some time. [account of Puryear vs. State of Texas in Court of Criminal Appeals of Texas, "The Southwestern Reporter," vol. 98, 1907, p. 258. The homicide at the center of the case took place in Austin, Texas, March 3, 1906]