Trouble with this sentence: 未曽有の被害をもたらした７月の西日本豪雨災害


> **未曽有の被害をもたらした７月の西日本豪雨災害** 。その災害から私たちを守ってくれるはずの避難所で、命の危険を感じて被災した自宅に
> **引き返した**
> 人たちがいます。「食物アレルギー」がある人や、アレルギーのある家族がいる人たちです。避難所にアレルギーに対応した食品がなかったため、避難所にとどまることができなかったのです。災害大国とも呼ばれる日本で、なぜ教訓が生かされないのか？被災地の１つ、広島県の自治体を通して見えてきた課題を取材しました。([source](https://www3.nhk.or.jp/news/web_tokushu/2018_1004.html?utm_int=tokushu-
> new_contents_list-items_003))

未曽有の被害をもたらした７月の西日本豪雨災害 means that ７月の西日本豪雨 is a disaster that has caused
unprecedented damages but I don't understand if we only talk about heavy rains
or all types of disasters(for the damage comparison), if it's unprecedented in
comparison to other heavy rains/disasters in western Japan, in Japan, or in
the world?

Also, I don't know what is the (omitted)object of the verb 引き返す(the verb
appears as transitive on
[jisho](https://jisho.org/word/%E5%BC%95%E3%81%8D%E8%BF%94%E3%81%99))?




未曽有の is a fixed no-adjective that literally means "unparalleled in history" or
"unprecedented", but it's merely a [Buddhism-
origin](https://japanese.stackexchange.com/q/39537/5010) fixed phrase and not
a technical term. (character-wise, 未 = not-yet, [曽 = in the
past](https://www.weblio.jp/content/%E6%9B%BD%E3%81%A6), 有 = exist.) You
should not take it too seriously and wonder what is compared with it.

If you are interested in the actual fact, [2018 Western Japan
Flood](https://en.wikipedia.org/wiki/2018_Japan_floods) is the deadliest one
caused by rain in the last 36 years in Japan (after [Nagasaki Flood in
1982](https://ja.wikipedia.org/wiki/%E9%95%B7%E5%B4%8E%E5%A4%A7%E6%B0%B4%E5%AE%B3),
which not many people remember), but of course there are [several deadlier
floods](https://en.wikipedia.org/wiki/List_of_deadliest_floods) happened in
this period in the world. This is the worst natural disaster that happened in
Japan after [Tohoku Earthquake in
2011](https://en.wikipedia.org/wiki/2011_T%C5%8Dhoku_earthquake_and_tsunami),
which everyone still remembers. Taking these facts into consideration, we can
say this 未曾有 is used in the sense of "worst one caused by rain in the last few
decades in Japan", but this does not mean 未曾有 itself has such a specific
definition.

引き返す meaning "to head back" is an intransitive verb. While the transitivity of
a compound verb tends to be determined by the second verb, there are always
exceptions, and jisho.org made a mistake. (They make tons of mistakes
regarding word class...)




未曽有の is a fixed no-adjective that literally means "unparalleled in history" or
"unprecedented", but it's merely a [Buddhism-
origin](https://japanese.stackexchange.com/q/39537/5010) fixed phrase and not
a technical term. (character-wise, 未 = not-yet, [曽 = in the
past](https://www.weblio.jp/content/%E6%9B%BD%E3%81%A6), 有 = exist.) You
should not take it too seriously and wonder what is compared with it.

If you are interested in the actual fact, [2018 Western Japan
Flood](https://en.wikipedia.org/wiki/2018_Japan_floods) is the deadliest one
caused by rain in the last 36 years in Japan (after [Nagasaki Flood in
1982](https://ja.wikipedia.org/wiki/%E9%95%B7%E5%B4%8E%E5%A4%A7%E6%B0%B4%E5%AE%B3),
which not many people remember), but of course there are [several deadlier
floods](https://en.wikipedia.org/wiki/List_of_deadliest_floods) happened in
this period in the world. This is the worst natural disaster that happened in
Japan after [Tohoku Earthquake in
2011](https://en.wikipedia.org/wiki/2011_T%C5%8Dhoku_earthquake_and_tsunami),
which everyone still remembers. Taking these facts into consideration, we can
say this 未曾有 is used in the sense of "worst one caused by rain in the last few
decades in Japan", but this does not mean 未曾有 itself has such a specific
definition.

引き返す meaning "to head back" is an intransitive verb. While the transitivity of
a compound verb tends to be determined by the second verb, there are always
exceptions, and jisho.org made a mistake. (They make tons of mistakes
regarding word class...)

