-ist
Added to words to form nouns denoting:
a person who studies or practices a particular discipline;
botanist, one who studies plants
psychiatrist, one who practices psychiatry
a person who uses a device of some kind;
violinist, one who plays a violin
bicyclist, one who rides a bicycle
autoist, one who drives an automobile
pianist, one who plays the piano
vapist, one who uses a vaping device
one who engages in a particular type of activity;
adventurist, one who takes risks or goes on adventures
artist, one who makes art
bigamist, one who commits bigamy
terrorist, one who causes terror
tourist, one who tours
Note, many of these are related to -isms: adventurism, terrorism, tourism
one who suffers from a specific condition or syndrome
autist, egoist
Note, these are related to -isms: autism, egoism
one who subscribes to a particular theological doctrine or religious denomination;
Calvinist, Baptist, deist
Note, these are related to -isms: Calvinism, deism
one who has a certain ideology or set of beliefs;
Marxist, modernist, nihilist, existentialist, fascist, pacifist, activist, environmentalist,
Note, these are related to -isms: Marxism, modernism, nihilism, existentialism, fascism, pacifism
one who owns or manages something;
capitalist; industrialist
Note, these are related to -isms: capitalism; industrialism
a person who holds bigoted, partial views. sexist, racist: Note, these are related to -isms: sexism, racism