noun
subjectivist
A person who adheres to subjectivism, especially in philosophy or ethics.
彼は主観主義者として、道徳は個人の感情に基づくと主張した。
As a subjectivist, he argued that morality is based on individual feelings.
Compound of 主観 (subjectivity) + 主義 (doctrine) + 者 (person).