bftnag 

pronounced (biff-t-nag.)
an acronym standing for either Best Friend That's Not A Guy, or Best Friend That's Not a Girl. Used in cases in which very good friends are of the opposite sex. a person has the same relationship with a bftnag as they would a best friend.

Phillip and Katie are bftnags. They tell each other everything, and have complete trust in one another.

bftnag by The Red Bull May 26, 2008

Bftagflam 

Best friend that's a guy for life and more.

"Billy is my bftagflam," Caitlin said.

Bftagflam by Emmers8D September 10, 2010

Bftag

Stands for "Best Friend That's a Girl" (for guys)

"Best Friend That's a Guy" (for girls)

Basically an acronym for a best friend of the opposite sex

Not to be confused with boyfriend/girlfriend

Arunn, yeah he's one of my best friends but Karthika, she's my bftag!

Bftag by Ch1nchilla November 17, 2010