grandfag

A person who has grandchildren, and they come out of the closet as gay.

Chris: Well hello GrandFag!
GrandFag: GRANDFAGGG!!

GrandFag

A grandparent that eventually turned gay.

Chris: well hello GrandFag.

grandfag

A grandparent who comes out as gay.

Chris: well hello GrandFag!
GrandFag: GRAAANDFAGG!!