-ist

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

pantisocratist (s) (noun), pantisocratists (pl)
A supporter of the belief that everyone is an equal member of the government: The children in the family were pantisocratists who favored and supported the theory of pantisocracy, but not the parents!
pantophagist (s) (noun), pantophagists (pl)
Someone or those who eat just about everything.
papyrogist
A student of papyrology.
papyropolist
A seller of paper.
parabaptist
parabolist
paragrammatist
A punster or someone who is fond of or skilled at making puns or a humorous play on words.
paralogist
parasitologist
parasitologist
An expert in parasitology.
parochialist
parthenolatrist
Someone who worships a virgin, or virgins; referring especially to the Virgin Mary.
particularist
paternalist
pathologist (s) (noun), pathologists (pl)
A medical doctor who specializes in identifying diseases by studying cells and tissues under a microscope: A pathologist is an expert who strives to determine the essential nature of diseases, especially of the changes in body tissues and organs that cause or are caused by diseases.