Two senses, primary first, then secondary:
- a person who emotionally and psychologically feels that they belong to the opposite sex
- a person who has undergone treatment in order to acquire the physical characteristics of the opposite sex
I was rather surprised earlier this year when I finally got my diagnosis to find that the medical profession follow the primary sense. Thus my psychiatrist, a doctor of some repute with way more letters after his name than I have and who has seen many hundreds of transsexuals over the years, described me as a transsexual. In his book it's a medical condition you can be treated for but you don't lose, the only way you can become a former transsexual once diagnosed is to be laid out cold on the slab in the mortuary. For him you can become a former gender dysphoria sufferer after treatment, but not a former transsexual.
So now outside the context of my psychiatrist, I don't describe myself as transsexual. I could come over all trans-fundamentalist and do so, but somehow I don't feel even after forty years a loner battling gender dysphoria that I've earned it. It's a personal choice, so by the same metric if someone who has earned it and has conquered their gender dysphoria describes themselves as a former transsexual then that's their personal choice too.
A happily transitioned trans friend of mine who attends my local support group, an archetypal granny in her mid sixties, is very relaxed about her chosen label. She once looked at me with a wicked grin on her face and stage-whispered in her most masculine voice: "I'm really a bloke you know!". She also has diabetes, for which she takes pills and has injections to keep it under control. I guess they're not unlike hormone tablets or injections in appearance, though I wouldn't know. I've never heard her describe herself as a former diabetic because of them though.