-ist

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

parasitologist
parochialist
parthenolatrist
Someone who worships a virgin, or virgins; referring especially to the Virgin Mary.
particularist
paternalist
pathologist
1. A doctor who specializes in identifying diseases by studying cells and tissues under a microscope.
2. A medical specialist who strives to determine the essential nature of diseases; especially, of the changes in body tissues and organs that cause or are caused by disease.
patrist, patristic
One versed in the lives or writings of the Fathers of the Christian Church.
pedagogist
A teacher of children.
pedobaptist (s) (noun), pedobaptists (pl)
A person who practices, adheres to, or advocates infant baptism.
pedodontist, pediadontist (s) (noun); pedodontists, pediadontists (pl)
A dentist who practices dentistry that deals with children's teeth.
pedologist, paidologist (s) (noun); pedologists, paidologists (pl)
A person who studies children and their behavior.
pedorthist
A person skilled in pedorthics and practicing its application in individual cases.
pedotrophist (s) (noun) ,pedotrophists (pl)
A person who is skilled or has the knowledge, the ability, or the training to bring up children properly.
pegologist
pegotherapist