Profesionista, a person who has studied a profession and practices it. The Diccionario del español de México of El Colegio de México gives the example un profesionista de gran valor, a professional of great worth.
Titularse, to obtain one’s professional title: “El año pasado se titularon casi todos mis compañeros de generación” (Last year almost all my classmates got their titles). Pasante, a person who has passed all the courses of a degree but has not yet taken the professional exam, as in un pasante de derecho, a law pasante.