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1.
The polite way to describe somthing that is "fucked up"
Jack muffed up Jason's face after Jason attempted to finger Jacks mothers asshole while she was sleeping.
by scott January 30, 2004
 
2.
muffed up means fucked up. use "muff" to replace fuck. very fun to use so you dont get in trouble by the parentals or offend the old folks. use different variations of muff too-muffer, muffing, etc.
That's muffed up dude!
Go muff yourself.
by Kyle Ernesti June 16, 2006
 
3.
synonym for fucked up.

slang term that is often used on Call of Duty Modern Warfare 2
Alex: Dude what did Sam do?

Tyler: He cried after getting high

Alex: Thats muffed up
by Alex Hildenbrand May 05, 2010
 
4.
In a way the same as Muff diving, but all over the place.
Damn...you got all muffed up!!!!!
by iohnoprngs March 22, 2009
 
5.
phrase referring to fucking up sex by not shaving your muff
We was about to hit it right, but i reached in, felt that bush and though "damn, this bitch muffed up." She knew she muffed up too.
by Fisherella June 30, 2009