いざという時とき

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Meanings

1

at the critical moment; when the time comes; in an emergency; when push comes to shove

Refers to a decisive or urgent moment when action is needed. Often used in contexts of preparedness or contingency.

非ひ常じょう時じN3
非常時 is a more formal, general term for an emergency or crisis situation, while いざという時 emphasizes the personal decisive moment when one must act.
有ゆう事じ
有事 is a formal, often political or military term for a time of crisis or war, whereas いざという時 is used broadly for any critical moment in daily life.

平へい時じ
平時 means peacetime or normal times, the opposite of いざという時, which points to a sudden critical or emergency moment.

いざN1
いざ is a standalone interjection urging action or marking a decisive instant, while いざという時 is the fixed phrase meaning 'at the critical moment' and cannot be used alone in the same way.

From いざ (an urging or decisive interjection) + という (quoting particle) + 時 (time), literally 'the time when one says いざ'.