A woman who you are not related to, or sexually active with, but consider as a bro.
Other variations: fe-broski, fe-brah, fe-bruh
Guy one - "Hey man, did you pick up your Warped Tour tickets yet?
Guy two - "No, but I'm gonna have Ashley pick them up for me, she said she would."
Guy one - "Man, she's such a good fe-bro."