noun which may take the genitive case particle 'no', noun
unprecedented; unheard-of; record-breaking
Describes an event or situation that has never happened before, often with a dramatic or serious tone. Commonly used in news and formal contexts.
The whole country was shocked by the unprecedented disaster.
未曾有の大雨で川が氾濫した。
The river flooded due to record-breaking heavy rain.
未曾有 is a literary term typically used for disasters or extraordinary events, while 空前 is common in news and statistics for records.
前代未聞 and 未曾有 both mean 'unprecedented', but 未曾有 is more formal and typically used for disasters or crises while 前代未聞 fits surprising news or achievements too.
Standard kanji spelling.
Variant with 曽 instead of 曾; less common but attested.
From classical Chinese 未曾有 (wèicéngyǒu), literally 'not yet ever existed'. The Japanese reading みぞう is a kan'on reading of the characters.