-ist

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

serologist
An expert in the science of the properties and reactions of serums, especially blood serum.
sesquilinguist
Someone who knows one and "a half" languages (or one and "part" of another language).
sesquipedalianist (s) (noun), sesquipedalianist (pl)
A person who uses excessively long words: "The vocabulary class had a contest to see which sesquipedalianists could come up with presentations of simple proverbs that have been turned into multi-syllable words."
silviculturist
sinoclamephilist
A collector of Chinaware.
Sinologist, sinologist (s); Sinologists, sinologists (pl) (nouns)
A student of Chinese history, language, and culture.
slabophilist
A collector of decorated tiles.
socialist
1. Someone who believes in or supports socialism or a socialist party.
2. An advocate of socialism or someone who is a member of a socialist party.
sodomist
One who practices sodomy.
solibiblist (s) (noun), solibiblists (pl)
Someone who depends only upon the Bible for truth and guidance.
solidarist
solidist
soloist
Anyone who performs a solo.
somatist
A psychiatrist who considers all mental illnesses to have physical origins.
somatotherapist