grandsister
When your sister marries your grandfather.
Dude your grandsister is totally hot.
Grandsister
The granddaughter of your sister.
DUDE YOUR GRANDSISTER CAN COOK? AWESOME!
Grandsister/Grandbrother
When your son/daughter has a baby with your mom/dad, said baby becomes the your grand-sister/grand-brother.
Today I'm taking my Grandsister/Grandbrother to the park.
grandsister
Your grandmothers sister.
boy 1: oh what a old hottie
boy 2: that's my grandsister
boy 2: that's my grandsister
grandsister
Grandsister is your grandmothers sister, yeee boiiiii
Boy 1: Ohh that old hottie
Boy 2: That's my grandsister.
Boy 2: That's my grandsister.
Grandsister
Idk ask me?
Bro your grandsister pooped her pants sus