The American Heritage® Dictionary of the English Language: Fourth Edition. 2000.
ist
SUFFIX:
1a. One that performs a specified action: lobbyist.b. One that produces, makes, operates, plays, or is connected with a specified thing: novelist.2. A specialist in a specified art, science, or skill: biologist.3. An adherent or advocate of a specified doctrine, theory, or school of thought: anarchist.4. One that is characterized by a specified trait or quality: romanticist.
ETYMOLOGY:
Middle English -iste, from Old French, from Latin -ists, -ista, from Greek -ists, agent n. suff.