Green’s Dictionary of Slang

(gay) a transgender, transsexual or transvestite person; thus as v. to change sex.

1998		R. Scott Rebecca’s Dict. of Queer Sl. 🌐 Trans — a catch-all term for anyone crossing gender or sex boundaries (transgender, transsexual, transvestite, etc.). Capitalized when referring to the community in general by those who view it as an ethnic designation similar to African American or Jewish.
2024		J. Meades Empty Wigs (t/s) 822: [T]he young Lionel Knave before he transed into Leonie Vane!