look up any word, like lemonparty:
 
1.
n. Derived from the ancient Roman acronym "BFNR" meaning "Boner For No Reason". A bifner usually occurs in non-sexual situations without warning and can last indefinitely. There are various methods for removing the bifner but the best is giving it time.
Correct Usage:"The other day I was watching the View and I got a massive bifner."

"I was sitting in Math class and I got a bifner."

Incorrect Usuage:"Out of nowhere I got a bifner." The definition of bifner already covers the unexpectedness.
by Matt Greco July 31, 2006
 
2.
When a male receives a boner that does not all the way erect, or when coming down from an erection and is currently right in the middle stage of completely coming down from the that erection. Better understood to be a "soft boner."
Mike: Hey did you see that chick?
Aaron: yeah I did, shes ok I would give her a 5 out of 10.
Mike: She's good enough to give me a bifner I suppose.
by Vessey December 07, 2009