滾瓜爛熟 gǔn guā làn shú

DEFINITIONS

  1. lit. ripe as a melon that rolls from its vine (idiom); fig. to know fluently
  2. to know sth inside out
  3. to know sth by heart

CHARACTERS

滾 gǔn turn, roll, rotate; boil
瓜 guā
HSK 2
melon, gourd, cucumber; rad. 97
爛 làn rotten, spoiled, decayed
熟 shú
HSK 4
well-cooked; ripe; familiar with