acronym for "fucking ugly motherfucker", can be used to describe an ugly person while in close range without them noticing the insult.
"Hey, Larry"
"What's up Billy?"
"See that F.U.M. sitting over there?"
"hell yeah. that's a FUM"
(SCREAMING)
F . U . M !
"What's up Billy?"
"See that F.U.M. sitting over there?"
"hell yeah. that's a FUM"
(SCREAMING)
F . U . M !
by BillynLarry2011 May 09, 2011
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