Xumgender, also known as pendogender is the state of never being satisfied with ones gender, no matter how well it fits, due to self-doubt or identity issues. This causes one to compulsively search and seek out something that fits even better- to find "the gender" or "the one truth"- though one will never be found due to A) One's neurotype. B) Words will never be able to describe one's gender. C) One's gender is paradoxical. This inability to find a "one true gender" frequent causes anxiety and doubt and can even cause the label xumgender to feel imperfect to the individual.
This term is exclusive to neurodivergent people. It was specifically coined with people with anxiety disorders, OCD, and OCPD in mind. The term implagender exists for neurotypical people who relate to this experience and don't want to appropriate.