noun
character sketch; commentary on personalities
A literary or historical term for a brief critical assessment of a person's character or conduct, often in the context of Chinese-style biographical sketches or evaluations. Rare in modern everyday Japanese.
彼は歴史上の人物について月旦評を書いた。
He wrote a character sketch about a historical figure.
この書
This book contains commentaries on the personalities of the literary figures of that time.
From Chinese 月旦評 (yuèdànpíng), originally referring to a monthly evaluation of officials' conduct in ancient China. The Japanese reading is げったんひょう, a Sino-Japanese on'yomi compound.