grandmotherfucker 

One who fucks a grandmother

Steve Stifler in American Wedding is a grandmotherfucker, since he fucks Jim's grandmother.

grandmotherfucker by Greg Pugh August 14, 2003

Grandmotherfucker 

Also known as your grandfather.
Named for mating with his wife to produce children who then become parents of his grandchildren.

Ben: Me and my motherfucker just went to see my grandmotherfucker for Motherfucker's Day (also known as Father's Day).
Gregory: My motherfucker (or my father) is such a charm and treats you with love.

Grandmotherfucker by gregben July 6, 2021

grand motherfucker 

When the regular motherfucker just doesn't cut it; a higher level of motherfucker.

It's going down now, you grand motherfucker!

grand motherfucker by The Great Dark February 8, 2015

Grand motherfucker 

A respected older motherfucker who has been promoted by excelling as a motherfucker or by fucking one or more grandmothers

John is now a Grand motherfucker.

Grand motherfucker by JAKINTEXES July 10, 2011

grandmotherfuckersonofabatchofcookies 

something Dane Cook would say

what Courtney calls Tom

you are such a grandmotherfuckersonofabatchofcookies

grandmotherfuckersonofabatchofcookies by <><><><><><><><><><><><> July 27, 2006