狸貓換太子 [－猫换－－]

Jyutping lei4 maau1 wun6 taai3 zi2
Pinyin lí māo huàn tài zǐ

Definitions (粵典–words.hk)
  1. 語句
    比喻​以假​貨換​走​珍貴​物品
    to substitute someone's valuable item with another item; literally: to substitute a leopard cat (?) for the crown prince
Definitions (Wiktionary)
  1. phrase, idiomatic
    to substitute someone's valuable item with another item