1) When someone doesn't care about how their gender looks from the outside
2) When someone displays a mix of traditionally "masculine" and traditionally "feminine" traits.
Genderfuck people are mostly queer, especially gender-wise, but they *can* be totally cisgender and heterosexual.
Person 1: "Bro, I'm genderfuck."
Person 2: "Is that even a thing?"
Person 1: "Yeah, it is."