this is so weird i was looking up the same thing (for a game i was playing) the answer was: journalist after searching under "ten letter occupations that end with 't' " i looked up " words that in 'ist' " and i found this site: http://wordnavigator.com/ends-with-by-length/ist/ i hope it helps!!!
usher
Optometrist
doorman
undertaker underwriter
Japayuki
rADIOLOGIST
lawyer
zookeeper zoologist
dentist
Teacher.
occupational theripist (OT)
Kitchen Salesman/lady