Transsexual

Transsexuality is when a person wishes to be the opposite sex or has undergone treatment to have the opposite sex.

Transsexual, by definition, is an umbrella term used to describe a person whose gender is emotionally/psychologically different from their sex assigned at birth. It is a more specific term under the transgender category.

Terminology
The term transsexual was first introduced by sexologist David Oliver Cauldwell and then later made popular by endocrinologist Harry Benjamin in 1966.