by stoner June 19, 2006

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.
by John Woods October 17, 2008

The unattractive girl that a hot girl keeps around to make herself and her friends look better. Stands for "Dumb Ugly Fat Friend". THe DUFF tends to be a cockblock or a third wheel. See also "Grenade".
by G. Sherman August 11, 2003

by hillary's ex April 12, 2004

She is up the duff
by Johan Forssander March 3, 2004

n. an inert substance used to dilute a narcotic such as cocaine.
The substance must be similar in appearance to the narcotic so as to satisfy the suspicions of the narcotic purchaser. The introduction of 'duff' to a narcotic increases the profit margin for the seller if the selling price of the product is not adjusted for the amount of duff introduced.
See also cut
The substance must be similar in appearance to the narcotic so as to satisfy the suspicions of the narcotic purchaser. The introduction of 'duff' to a narcotic increases the profit margin for the seller if the selling price of the product is not adjusted for the amount of duff introduced.
See also cut
"This shit isn't anything but duff!" A phrase one may use when the narcotic purchased for one's pleasure does not administer the desired effect.
by Oreck December 28, 2005
