grandsispa 

A person(s) that is your grandfather, sister, brother, and father.

Hey, today I’m going to visit my grandsispa in London.

grandsispa by JaxtheBrainstorm April 10, 2019

grandspawn 

grandchild, especially one of questionable origins. Comes from the tv series Angel, when the Fang Gang learns that Cordelia has been impregnated by Angel's demon-spawned son Connor.

Gunn to Angel: "Congratulations, you're going to have a grandspawn." (Season 4, episode 16)

grandspawn by braxxx October 17, 2008

Grandpaspaghetti

A tiktok creator who comments under nearly every post with “grandpa lol”.

*opens up a tiktok videos comment section

Grandpaspaghetti: grandpa lol.

Person: You’re everywhere bro!

Grandpaspaghetti by grandpaspaghetti April 1, 2021

grandsister 

When your sister marries your grandfather.

Dude your grandsister is totally hot.

grandsister by Big Man25 January 8, 2011

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/Grandbrother by Nullivoid December 21, 2020

Grandsister 

The granddaughter of your sister.

DUDE YOUR GRANDSISTER CAN COOK? AWESOME!

Grandsister by Twight0931 July 30, 2017

grandsister 

Grandsister is your grandmothers sister, yeee boiiiii

Boy 1: Ohh that old hottie
Boy 2: That's my grandsister.

grandsister by tjingtjong112 May 9, 2019