1 definition by mandi van a.

derived from the abbreviation "BFF" which stands for "best friend(s) forever."

noun: one's best friend, a term of endearment.

adjective: a way to describe and/or name your best friend.
"do you know that girl morgan smith?"
"of course, she's my biff!"

best friend: "oh i'm so upset!"
you: "what's wrong, biff?"
by mandi van a. April 7, 2008
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