How about "gender refusnik"?
My "gender identity," such as it is, is mostly something I assume as a convenience for other people, who generally don't know how to deal with you unless they can slot you as "male" or "female." For myself, I don't particularly identify on the basis of sex/gender, but more on the basis of values (more or less what in the USA used to be called "liberal") and way of looking at the world (techie.)
In some ways, I fit into the usual expectations of my sex (male), in other ways I don't, and I've reached an age where I don't give a **** if people are bothered by the ways I don't.
tl;dr: On the outside I'm male. For the purposes of basic interactions, I make a rudimentary effort to pass. But inside, I have no sex/gender, at least none that I care about. And I resist other people's efforts to assign me one and then make me act in accordance with their idea of my "gender identity."