-ist
(Greek > Latin: a suffix; one who believes in; one who is engaged in; someone who does something)
Someone who has a dread of drinking too much wine or has a strong negative feeling about drinking anything that is alcoholic: Herald was an oenophobist who avoided going to parties, social gatherings, and local pubs where fermented beverages were served because he didn’t want to observe other people who were making fools of themselves.
oligopolist, oligopolists
Someone who is part of a small number of producers or sellers.
A specialist who analyzes rain conditions and how they affect the environment.
omnist
omophagist
A person who eats raw flesh.
omphalomantist
oncologist, cancerologist
A doctor who specialises in the diagnosis, treatment and rehabilitation of individuals suffering with cancer.
oneirologist
A specialist in oneirology or the study and interpretation of dreams.
oneiropolist
Someone who interprets dreams for a price.
oneiroscopist
A specialist in the analysis of dreeams.
onomantist, onomomantist
Someone who divines or foretells the future with names.
onomatologist
Someone who is versed or is a specialist in the history of names.
onychomantist
Someone who predicts a person’s future by the appearance of the fingernails themselves.
onychophagist (s), onychophagists (pl) (noun forms)
Those who chew on their fingernails: "Some onychophagists try to avoid letting others see their nail biting habits, but quite often they are so upset that they can't help themselves."
oologist