Cassgenderfaun is a subset of cassgender where one feels that their gender is unimportant or where one is indifferent to the idea of gender, but knows that they don't have a female or feminine gender. Cassgenderfaun is different from a lack of gender, as a cassgenderfaun individual might have a gender but not feel that it's an important part of their identity.
The feminine counterpart is cassgenderfae. A related term is cassflux, where the level of indifference fluctuates.