noun
hedonist; epicurean
Refers to a person who pursues pleasure as the highest good, often in a philosophical or lifestyle sense. 'Epicurean' here is used in the popular sense of a pleasure-seeker, not strictly the philosophical school.
彼は快楽主義者で、人生は楽しむためにあると考えている。
He is a hedonist and believes that life is meant to be enjoyed.
快楽主義 is the abstract concept of hedonism, while 快楽主義者 refers to a person who follows that philosophy.
Compound of 快楽 (pleasure) + 主義 (principle, -ism) + 者 (person). The term is a straightforward Sino-Japanese construction.