不郎不秀

idiom

mediocre; useless; a good-for-nothing; neither fish nor fowl

Originally, during the Yuan and Ming dynasties, the sons of nobles and high officials were called 'xiù' (秀), while the sons of commoners were called 'láng' (郎). This phrase, meaning 'neither xiù nor láng', thus described someone who falls into neither category – essentially, an unaccomplished, useless person. Used primarily in literary or historical contexts to criticize a lack of ability or ambition.