吞蛋 [－－]

Jyutping tan1 daan2
Pinyin tūn dàn

Definitions (CC-CANTO)
  1. lit. swallow an egg, meaning to score nil or no marks in a sport match or exam
Definitions (粵典–words.hk)
  1. 動詞
    攞​零分​；​攞​零​雞​蛋
    to get a zero score; literally: to swallow an egg