Duff 

UK - to be pregnant

She's up the duff

Duff by Sophie96 April 11, 2015

Duff 

Designated ugly fat friend

Duff - a less attractive person who has really hot friends and is an easy target to talk too while out at a party/bar too hook them up with the hot friends

Duff by Eloks July 29, 2015

DUFF 

Acronym meaning designated ugly fat friend. This is the disgusting ugly fat friend that tags along with the hot chicks. Said hot chicks allow this as it makes them look less shallow and more attractive.

Ian: I've been tryin' to get Jenna alone for weeks now, but Bertha's always around.

Shawn: Ew, dude, Bertha's a total DUFF.

Ian: You think you could hold her attention while I talk to Jenna?

Shawn: That depends on how much you're willing to pay me.

DUFF by xdanielx October 3, 2008

duff 

1. Designated Ugly/Fat Friend
a friend that hot girls have to make themselves feel hotter
2. someones butt

1. Every hot girl I see seems to have a duff
2. Get off yer duff and do some work!

duff by Poopie pants 2 December 2, 2007

DUFF 

Designated Ugly Fat Friend/Designated Ugly Fat Fuck/Dumb Ugly Fat Friend

The infameous beer that Homer Simpson drinks on The Simpsons

a teenage pop star who has some talent but is over shadowed for being a "poseur"

That girl is a TOTAL DUFF

Homer Simpson always drinks Duff beer.

Hilary Duff is alright but everyone calls her a "poseur"

DUFF by Mike December 28, 2005

Duff 

Designated Ugly Fat Friend not to be confused with the fuckin amazing duff mckagan. This person often makes you feel better about yourself when your around them...they make you look good

my friend lindsay is a duff when we go out

Duff by slashsbabe_420 June 13, 2007

DUFF 

The Dumb Ugly Fat Friend. Every hot girl has one, and their objective is to cock block all the guys. And for every DUFF you need a grenade and thats ur friend that would try to hit anything.

WOW! that DUFF's a bitch.

DUFF by ATICUS September 11, 2006