Sister Fiend 

One who continually pursues his friend's sisters. Will go through great lengths despite complete futility along with a consistent beating.

You've been talking to my sister on facebook, you're following his sister on twitter, nigga you a sister fiend!

Sister Fiend by just some guy typin some shit. February 1, 2013

Sisterfriend

A sister friend is when you have one sister that also doubles as your best friend.

My sisterfriend is the only person actually nice to me.

Sisterfriend by What the boo boo boo ra ra ra June 1, 2020

Sisterfriend

Your sister, your only sister. She is your sister but a friend and the most amazing one at that.

First slurred out when I was drunk because there was no one word invented for her yet.

Sisterfriend is the best of both worlds: First she is your blood- Second she is your friend-confidant-reality check. Sometimes you fight and sometimes you get ridiculous with each other. She is a friend that will always be there because she has to- she's your sister duh!!!

I heart my sisterfriend so much but I'll slap that bitch if she borrows my clothes without asking again.

Sisterfriend by Callcp May 14, 2012