BFG stands for
Best Friend Gayle
A spin on Oprah's infamous
reference to her friend Gayle King. Whenever she mentions Gayle, she doesn't merely say "Gayle" she always says "best-friend-gayle."
Use this phrase to describe any same-sex
best friend.
This works especially well when introducing a friend who is ONLY a friend, but often mistaken for a lover.
Can also be shortened to BFG.