-ist

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

phycologist
physiatrist
1. A physician who specializes in physiatrics.
2. A physician who specializes in physical medicine.
3. A health care professional who administers physical therapy; a physical therapist.
physicist
A scientist who specializes in physics.
physiognomist
1. Someone who practices physiognomy, a pseudoscience, based on the belief that the study and judgement of a person's outer appearance, primarily the face, reflects his/her character or personality.
2. Scientific correlation physiognomy, in which there are believed to be rough statistical correlations between physical features (especially facial features) and character traits due to a person's physical preferences that are caused by corresponding character traits; such that gene mixing causes the correlations; this type of physiognomy is therefore based on genetic determinism of character.
physiologist
1. A natural philosopher; a naturalist who is engaged in the biological study of the functions of living organisms and their parts.
2. Someone who studies the functions of a living organism or any of its parts.
3. A biologist specializing in physiology.
physiotherapist
1. A person who uses physical methods to treat certain ailments.
2. Someone who is competent and qualified to administer physiotherapy.
physiotherpeutist
phytogeographist (s) (noun), phytogeographists (pl)
Someone who writes descriptions about the geographical distribution of plants: In comparison to Greg's father, Mr. Timmons was a phytogeographist who had published many articles about the geographical scattering or spreading of plants.
phytographist
A person who specializes in the descriptions of seaweeds.
phytophilist (s) (noun), phytophilists (pl)
A collector of plants: Jack loved botany and wanted to have as many kinds of plants, like flowers, shrubs, bushes, and trees, in his garden as possible, and his friends said that he certainly was a phytophilist.
phytosociologist
Someone who specializes in that aspect of ecology dealing with the origin, composition, structure, and classification of plant communities.
pietist
pirinophilist (s) (noun), pirinophilists (pl)
A collector of cotton reels: Since Jane loved sewing and weaving, and as a pirinophilist, she had acquired quite an assortment of spools and bobbins that were used to keep cotton thread neat and orderly, but she used only the new ones that fit her sewing machine and spinning wheel.
piscicapturist (s) (noun), piscicapturists (pl)
A fisherman or a catcher of fish: "There are many men in the world who are piscicapturists as a profession or just for the sport of doing it."
pisciculturist
Someone who breeds and rears fish for scientific or commercial purposes.