Green’s Dictionary of Slang

motherfuck! excl.

also motherfug!
[motherfuck n.]

(orig. US) a general excl. of surprise, rage etc.

[US]R. Gover One Hundred Dollar Misunderstanding 21: Madam alla time tellin us cats, Don’ never say motherfug roun them real fay tricks, but Kee-ryees!
[US]C. Bukowski Erections, Ejaculations etc. 51: You what? you need a deep-sea diver? motherfuck!
[US]D. Goines Inner City Hoodlum 15: Motherfuck! Sam’ll give us a goddam hundred and fifty for each box!
[US]S. King Roadwork in Bachman Books (1995) 447: ‘Mother-fuck,’ he cried, ‘Oh, holy mother-fuck, Freddy, you cock-knocker!’.
[US](con. 1968) W.E. Merritt Where the Rivers Ran Backward 218: Mother Fuck. We oughta just split.
[US]W. Shaw Westsiders 270: He ends it [i.e. a song] by saying loudly into Todd’s mike: ‘Motherfuck!’.