駟馬難追 [驷马难－]

Jyutping si3 maa5 naan4 zeoi1
Pinyin sì mǎ nán zhuī

Definitions (Wiktionary)
  1. phrase, idiomatic
    words cannot be taken back once they are spoken
Examples (Tatoeba—Mandarin-English)
  1. Mandarin
    一言既出，驷马难追。
    一言既出，駟馬難追。
    yī yán jì chū ， sì mǎ nán zhuī 。
    • You cannot take back what you have said.