noun
virtuous person; moralist
Refers to a person who lives by strong moral principles or actively promotes morality. Can be neutral or slightly old-fashioned depending on context.
彼は厳格な道徳家として知られている。
He is known as a strict moralist.
Compound of 道徳 (morality) and 家 (person, specialist). The derivation is straightforward; no uncertain historical elements.