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1 definition by A Mumf

 
1.
MUMF

(n.) abbreviation

Mean Ugly Mother Fucker. Usually referring to a gentleman of large physique, generally over 6ft with a Viking/biker like appearance, often astride a motorcycle.

When no riding like a twat can often found in biker bars, drinking copious amounts of alcohol and leading a life of debauchery and mayhem.
In conversation

"Who's that big chap over there, hitting people?"

"Oh, it's a MUMF, best not to fuck with him"
by A Mumf February 02, 2010