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best friend, generally the ultimate best friend

derived from the word bffl
Elendea is my biff, we have known each other for 6 years.
by Nicole June 15, 2006
stupid shit bullshit stupid ass
Man Jim a really biff
by Jessica April 22, 2004
To have an epic fail or get seriously hurt.
"Dude that skate boarder just BIFFED it." "Hey did u hear that a kid BIFFED it down the stairs by the school."
by DeltaSnipr April 09, 2010
v. To strike or punch; n. A blow or punch.
This fist is going o biff you!
by Exploding Boy February 09, 2003
(n) a vagina
her biff is mad sexay
by missy November 24, 2002
Best Internet Friends Forever
Internet Buddy #1: Will you be my BIFF?
Internet Buddy #2: Oh really? Do ya mean it?

Internet Buddy #1: Yep.
Internet Buddy #2: Yes, yes of course I will be your BIFF.
by Captain "Soap" MacTavish February 20, 2010
The nemesis of Marty in the Back To the Future film series. Marty manages to encounter several different relatives of the Tanner family throughout the three BTF movies.
Biff - "How about you make like a tree, and get out of here!"
by Lon September 01, 2005