-ist

(Greek > Latin: a suffix; one who believes in; one who is engaged in; someone who does something)

theurgist (s) (noun), theugists (pl)
Someone who practices the art of securing the intervention of supernatural powers in human affairs: A theurgist is considered a wonder worker or magician because of his or her access to supernatural sources."
timbrophilist
A collector of postage stamps.
timothophilist
A collector of whistles.
titlist, titlists
Someone who holds a title as a champion: "He was the heavyweight titlist."
tocologist, tokologist
One who is a specialist in parturition (child birth); an obstetrician.
tolerationist
tonometrist
Someone who uses an instrument, such as a graduated set of tuning forks, to determine the pitch or vibration rate of tones.
toponymist
A person who utilizes a place-name, or a name given to a person or thing, marking its place of origin.
toxicologist
toxophilist
A collector of bows and arrows.
trachelologist
A specialist in the study of the neck and its injuries and diseases.
tractenjophilist
A collector of steam rollers.
tragematopolist
1. A seller of sweets; such as, candy or dried fruit.
2. Confectioner, someone who makes confections (sweet preparation of fruit, candy, cakes, cookies, etc.) to sell.
transcendentalist (s) (noun), transcendentalists (pl)
1. Someone who believes that reasoning is the key to understanding reality: One of the most famous transcendentalists was Ralph Waldo Emerson who believed and wrote about the importance that everyone should be self-reliant or self-sustaining.
2. Anyone who asserts that true knowledge is obtained by faculties of the mind that go beyond sensory experiences: Margaret Fuller, a transcendentalist of the 19th-century, was one of the philosophers who advocated that the spiritual reality rises above the scientific and empirical facts and entities of this world.
traumatologist (s), traumatologists (pl) (nouns)
A surgeon who practices traumatology, or a medic who is on duty at a trauma center.