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1. fumf
short for f#!k you mother f*^$&r
'Man you suck'
'fumf, ill beat your ass'
2. fumf
fumf - fucked up motherfucker

Usually used if we are describing someone crazy or out of their mind.
John: Hey man! Did you see James?! He was driving 150 MPH on this short, narrow street!

Jerry: Yeah. He really is a fumf.
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