性命關天 [－－关－]

Jyutping sing3 meng6 gwaan1 tin1
Pinyin xìng mìng guān tiān

Definitions (Wiktionary)
  1. phrase, idiomatic
    Synonym of 性命交關／性命交关 (xìngmìngjiāoguān, “to be a matter of life and death; of vital importance”).
    (syn.) 性命交關, 性命交关