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1.
Your boyfriend on facebook. He could live very far away, be in a relationship, or both. You trade messages and emails but never see each other in person.
I'm single, but I'm in love with my fbbf.
by RealNaughtyRN January 17, 2010
 
2.
(Face Book Best Friend). (n) a person that you do not know at all, but for some reason feel the need to respond to any number of your posts as a close friend.
Sally: No feeling 100% percent today.

FBBF: I am so sorry to hear that.

Sally: Thanks, to my newest FBBF.
by Istvan Sengir May 14, 2010
 
3.
Achronym for Furball Best Friend; A well fawned of friend, when at rest, resembles a ball of fur.
My dog, Gizmo is my FBBF.
by YumiSpewns May 28, 2010
 
4.
A boyfriend that is only existent on FB and is only FB official.
Sarah:So your my FBBF now?
Brett:Yepp if you will accept my relationship request.
by Getmygwallados August 06, 2010