万まん一いち

noun

emergency; worst-case scenario; unlikely event

Refers to a highly unlikely but serious situation; often used in conditional or hypothetical contexts. The literal gloss '10000 to 1' is a figurative expression of extreme unlikelihood.

• 万まん一いちのことがあったら、この番ばん号ごうに電でん話わしてください。

  If something should happen (in the unlikely event of an emergency), please call this number.

• 万まん一いちに備そなえて保ほ険けんに入はいっておく。

  I have insurance just in case (to prepare for the worst).

adverb, noun which may take the genitive case particle 'no'

if by any chance; in the unlikely event that

Adverbial use expressing a remote possibility; often paired with conditional forms like ～たら, ～ば, or ～ても.

• 万まん一いち雨あめが降ふったら、試し合あいは中ちゅう止しです。

  If by any chance it rains, the game will be canceled.

• 万まん一いちのことがあっても、慌あわてないでください。

  Even in the unlikely event that something happens, please don't panic.