命懸一線 [－悬－线]

Jyutping meng6 jyun4 jat1 sin3
Pinyin mìng xuán yī xiàn

Definitions (粵典–words.hk)
  1. 形容詞
    遭遇​生命​危險​，​少少​差錯​都​會​無命​。
    one's life being in imminent danger; literally: life hanging on a thread