まんいち 万が一 Common word LinksSentence search for 万が一Sentence search for まんがいちSentence search for まんがいつKanji details for 万 and 一Edit in JMdict Adverb (fukushi)1. (if) by some chance; by some possibility; in the unlikely event that; 10000 to 1See also 万一まんがいち万が一きがか気が変わったら、し知らせてくだ下さい。If you change your mind, let me know.Noun2. (unlikely event of) emergency; the worst(-case scenario)See also 万一まんがいち万が一にそな備えて、ぶき武器になるものをさが探した。I looked around for a weapon just in case.Other forms万が一 【まんがいつ】 Discussions Log in to talk about this word.