the act of locking the door behind you when you arrive to your place to lockout someone who may intrude or barge in unexpectedly.
"Hey did you duff the lock? Yeah man, don't worry I duffed it."
by Pants007 January 20, 2009
Dark brown or black cannabis remaining in a vaporizer bowl after vaporizing. The duff, which still contains some THC, is recycled rather than discarded by stingier enthusiasts.
Whoa, don't toss that duff, man! I'm saving that to make hash.
by John Woods August 25, 2008
A person who by society's description doesn't fit in with their friend group, being more approachable, and the one to go to ask for their friends numbers.
Guy: Heyyyyy


Guy: Well, i was thinking... would you like to...

Duff: Yeah...?

Guy: What's the hot girl on the left that you were talking too's number...?
by satan666jks May 27, 2015
(Da Ugly Fucking Friend) A term to describe the less attractive females another female will have in company to make her seem more attractive or just a less attractive friend to more attractive female. (Originating in Bear, Delaware)
Jon: "Hey! did you see that girl that just walked by?"

Brandon: "Which one?"

Jon: "The one in the middle bro!"

Brandon: "Oh yeah, but she's only a 6 on a scale of 1-10 without those DUFFs."

Jon: "Yeah her other friends were pretty ugly."
by Boogey Man Brown October 05, 2011
Scottish slang for a vagina

Also means something is rubbish, crap or broken
I'll kick you in the duff

That's totally duff
by Freakosaurus November 17, 2006
UK - to be pregnant
She's up the duff
by Sophie96 April 11, 2015
UK - to be pregnant
She's up the duff
by Sophie96 April 11, 2015

Free Daily Email

Type your email address below to get our free Urban Word of the Day every morning!

Emails are sent from We'll never spam you.