duff 

Designated Ugly Fat Friend.

That 3rd girl is definitely the duff of the group.

duff by G January 2, 2004

Duff 

A real term used in the heydays of Cocaine frenzy, 70s, 80s. Duff refers to that portion of your cocaine that consists of powder only, usually full of cut or anything else but real cocaine.

Shit, I won't buy from that dude again, this is all duff.

Duff by Gojai August 30, 2017

duff 

A simple pudding eaten by 19th century sailors. This was given to the crew once or twice a week at the most if they were working hard, or if the captain wanted to motivate them. Consisted of flour, boiled water, and whatever available fruit or molasses. Considered to be quite a luxury.

Having been unruly, the crew did not receive duff last Sunday.

duff by electronic_rodent April 13, 2008

Duff 

Designated,ugly,fat friend.

You don't necessarily have to be fat,or ugly to be one. the duff is considered a duff when he/shes significantly less attractive out of the group of friends they hang out with and both boys and girls can be one.
They are often used to get information about his/her friends.

1# "Damn, those girls are hot...well except for that one"
2#"yeah..maybe we can get some info on them from her?"
also shown in the movie"The Duff" if you need a visual example.

Duff by Guade April 2, 2015

duff 

UK usage

1) Something that's flawed or faulty

2) To duff up, to assault, beat up etc

He sold me a duff DVD so I duffed him up.

duff by black flag May 31, 2004

duff 

Bottom; bum; posterior; arse.

Get off your duff and help me with these dishes!

duff by Anonymous January 3, 2003

duff 

A unattractive female who is always seen with another female who is marginally more attractive. It is usually impossible to score with the hotter female without the duff receiving her fair share of the action.

Damn! I so wanna tap that chick.. but goddamn, she always has that duff Nicole hanging off her. Look at that fat mess!

duff by Steve0 August 20, 2004