Genderfirthet is a form of genderfluidity in which someone is only fluid between genders that are in some way connected to masculinity or femininity, but they are never completely female. A genderfirthet person never experiences genders that are completely abinary (removed from masculinity or femininity). They are also never a binary woman. They can be a binary man. For example, a genderfirthet person could experience genders like man, androgyne, demiboy/demigirl, proxvir/juxera, libramasculine/librafeminine, etc. They would never experience genders like binary woman, neutrois, maverique, agender, etc.
History
The first apparent mention of genderfirthet is on Tumblr user Gender-Resource's April 2020 Gender Jargon list[1]. There does not appear to be any other coining post. No flag for the term exists.