noun
Refers to a person who practices self-denial and abstains from worldly pleasures, often for religious or philosophical reasons.
彼は禁欲主義者で、贅沢を一切しない。
He is an ascetic and indulges in no luxuries at all.
Compound of 禁欲 (abstinence) + 主義 (principle, -ism) + 者 (person). The exact historical derivation is uncertain, but the term follows a standard pattern for forming nouns denoting adherents of a doctrine.