passing
What does passing mean?
When a trans person is perceived by others as cisgender — i.e. read simply as a man or a woman, no questions asked. For some it brings safety and ease; passing privilege can mean less harassment, less danger, better treatment. But it's a loaded word. Not every trans person wants it or chases it, and plenty push back on the framing — 'passing' quietly implies you're passing as something you're not, which a lot of people reject. Originally pulled into queer use from the older sense of passing across a racial line.
Origin
Adapted into trans/queer usage from the broader social sense of 'passing' (e.g. racial passing), where being perceived as a member of a group grants safety or access.