expression, noun
matter of life and death
A fixed expression used to describe a situation or issue that is extremely serious, potentially fatal, or of critical importance.
これは生死に関わる問題だから、慎重に判断しなければならない。
This is a matter of life and death, so we must judge carefully.
医者にとって、患者の生死に関わる問題は日常茶飯事だ。
For doctors, matters of life and death for patients are everyday occurrences.
死活問題 also means a matter of life and death, but often emphasizes survival or existential threat, especially in business or organizational contexts.
A compound phrase consisting of 生死 (life and death), に関わる (concerning, relating to), and 問題 (problem, issue). The expression is transparent and follows standard Japanese grammar.