mdfk 

Harsh swearing for polite surroundings

When pronounced phonetically, MDFK becomes 'mudderfucker' a simple slang abreviation of 'mother fucker', a popular insult.
therefore, M.D.F.K=mother fucker

that son of a bitch is one serious m.d.f.k

mdfk by Rich February 1, 2005

MDFK 

Stands for "Motherfucking Deadpool's Fan Klub", a humorous and irreverent name for fans of the Deadpool franchise — named after the expletive often coming out from the character's foul mouth.

I just joined the MDFK — can't wait to geek out over all the chimichangas Deadpool gives to fellow fans!

MDFK by Emotional Cruiser July 11, 2025