Mother-fucker means you fuck mothers or your own mother. I always thought it was an accusation of incest. Call some one a father-fucker or a brother-fucker it's funnier.(if your culture does stuff like that among friends) Words are not moral actions but if your a pc mother-fucker you think they are. If you think that way your likely too be that person who commits violence toward another because the shape of the air leaving the lungs of another person hurts your fee fees. It isn't taboo to kill mothers it is Illegal. It is taboo to pee on the floor and not clean it up. "Also, I'm pretty sure 'motherfucker' is an expression used on a bad person who 'fucks mothers', as in a bad husband\ father, because 'fucking' as opposed to 'making love', is something animalistic, aggressive even, it ignores the mother (woman) as a thinking, feeling, emotional being. So a 'motherfucker' is someone who treats a mother (woman) as a sex-object" That is not a definition I have ever heard of . It also sounds naive way of thinking about women that is puritanical. I interpret the colloquial usage to be " hey your a shifty person that would fuck your friends mother if you got the chance." Means your untrustworthy but no one uses that word in a serious way anymore because it is over used as a stereotype of African-Americans. It is now mothafucka. Anway off topic sorry.