advocate; ideologist; ideologue
Refers to a person who actively supports or promotes a particular theory, principle, or ideology. Often used in formal or intellectual contexts.
He is known as an advocate of liberalism.
-ist (adherent)
Suffix attached to nouns denoting a belief system or principle to form a word for a follower or adherent. Very productive; e.g., 平和主義者 (pacifist), 菜食主義者 (vegetarian).
She is a vegetarian and doesn't eat any meat.
He calls himself a pacifist, but his actions are contradictory.
She is a devoted environmentalist.
He calls himself a democrat, but in reality he's authoritarian.
主義者 specifically denotes an adherent of a named -ism (often formed by attaching 主義者 to a doctrine word), while 信奉者 more broadly means a devoted believer or follower of any idea, person, or religion.
支持者 means a supporter who backs a person, policy, or cause, whereas 主義者 implies deeper ideological commitment to a system of belief.
主義者 is someone who advocates for a doctrine, while 反対者 is someone who opposes it.
主義 is the principle or doctrine itself, while 主義者 (with the added 者) refers to the person who holds that principle.
The everyday counter for people: 一人 (ひとり), 二人 (ふたり), 三人 (さんにん).
名 is used instead of 人 in more formal or written contexts when counting 主義者.
voluntarist
egoist
intellectualist
subjectivist
humanitarian
Compound of 主義 (principle, doctrine) + 者 (person). The suffix usage is a direct calque from Western '-ist' formations.
totalitarian
communist