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.
This is a matter of life and death, so we must judge carefully.
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.
Standard kanji spelling for this fixed expression.
Kana spelling of 関わる is also common and avoids potential kanji confusion.
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.