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BLF is an acronym for Best Lady Friend. A female friend that's on the top of your close-friends list. It is a platonic relationship. Usually guys use this term to describe the relationship he has with the woman he hangs out with all the time, if she is not his girlfriend.
Vince: Yo Dude! You going out with Violet?
Dude: Nah, she's just my BLF.
Vince: O ok, 'cus I always see you guys together so I assumed she's your girlfriend or something.
by awesomagic October 21, 2011
1) An acronym for Blown Load Fruit Salad. A salad consisting of Cantelope, Cool Whip, romaine lettuce and human sperm.

2) Any fruit salad containing human sperm.
"I serve the fruit salad (affectionatly referred to as BLFS, or "Blown Load Fruit Salad") to my roommates and female friends, who have no idea that they are actually eating my blown load."
by The Lightning Stalker August 02, 2005