Unlike son of a bitch which is in reference to ones canine mother, son of a motherfucker is in reference to ones father that it is assumed was a motherfucker.

Can also be used as a curse when frustrated or infuriated by something.
Ask Doug?! Why, I wouldn't trust that son of a motherfucker as far as I could throw him.

What is wrong with this goddamn remote?! Son of a motherfucker!

After spilling your cereal all over the floor:
Oh, man. Son of a motherfucker! Shit!
by Mr. Wisdom August 27, 2009
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A much more powerful word than motherfucker, and can be used as a comeback when someone calls you a motherfucker. This word can also be used to imply that the victim's parent is a motherfucker, and also gave birth to a motherfucker. Destroy those bitches with this simple compound word!
Bob: "You're a motherfucker!"
Bill: " Well, you're a son-of-a-motherfucker!"
*Bob dies*
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