noun
absolutist
Refers to a person who adheres to absolutism, especially in political or philosophical contexts.
彼は絶対主義者として、君主の権力を支持している。
As an absolutist, he supports the monarch's power.
絶対主義 is the abstract concept of absolutism, while 絶対主義者 refers to a person who holds that belief.
Compound of 絶対 (absolute) + 主義 (doctrine, -ism) + 者 (person).