look up any word, like swag:
Designated Unpopular Fat Friend. A fat person,usually a female who is obsessed with a country boy,his friends,his momma,sister,truck and dog.
Girl: Where did all my ice cream go?
Boy: The duff must have ate it.
by brotherman94 January 21, 2012
1.A incognito way to compliment a nice behind without being heard or looked at by the selective the female target.the term started in NJ in the summer of 2007 and is now being used by college students,frat brothers and perverts up and down the east coast!

2.Nice Big round mound of butt that defies the laws of physics.
1.Jimmy have you seen "Billy Duff"? (while pointing out a target)
2.I was strolling down the beach earlier and saw a "Duff".
3. "Duff" to the right!
4. That's quite a large "duff".
by Joemy mckenzanela November 16, 2010
To catch a fart in your hand and put in someones face. A duff is similar to a fast ball, however it is not thrown.
Can I duff you?" "Yeah, duff me! Gimme yer duff!
by Andrea, St. Petersburg, FL September 11, 2010
the residual left in the bag of narcotics; the powder.
Dude... Where's all the rocks? That's just a bag of duff!
by sophuct72 February 05, 2010
A unit of measure that quantifies the rigidity (hardness and gurth) of an erection.
"This girl I destroyed last night was so hot, I swear my dick was pulling seven or eight duffs, bro."
by Pip3s November 02, 2009
To Fart, flatulate, passing intestinal gas, let one go, squeeze cheeks, float an air biscuit.
"Has someone done a duff? It smells in here."
by Animal Muppet June 10, 2009
Designated Ugly Fat Friend---Usually hangs around extremely Hot girls and DUFF's usually tend to be girls themselves
Bruh do u see dat D.U.F.F. hangin wit Jennifer
by WM-Dawg March 27, 2008