transsexual

Short definition from Wiktionary

Adjective

1. 1
   Of a person, having changed, or being in the process of changing, physical sex by undergoing medical treatment, such as hormone replacement therapy (HRT) and/or optionally sex reassignment surgery (SRS).
2. 2
   Of or relating to such a change.

Noun

1. 1
   A transsexual person.