How to say "sudden" in Japanese
Choosing the right word
- 急きゅうna-adjectiveThe most compact of these near-synonyms, but it seldom stands on its own in a sentence; you mostly meet it inside larger expressions for things that happen abruptly or unexpectedly.
- 突然とつぜんno-adjective, na-adjective, adverbThe all-purpose choice when something happens without warning — an event, a change, an appearance — with no special emphasis beyond the abruptness itself; if unsure which word fits, start here.
- 急激きゅうげきna-adjectiveDescribes change that is not merely unexpected but rapid and sharp — a steep rise, a quick worsening — where the pace of the change is the point; not the word for a one-off surprise.その党は急激にのびた。↗The party gained ground rapidly.
- 不意ふいna-adjective, no-adjectiveHighlights that an event was unforeseen and catches the person off guard; the surprise on the receiving end matters more than the speed of the event itself.
- na-adjective, no-adjectiveCovers things that spring up abruptly on the spot, with a shade of 'immediate'; usually written in kana. Narrower than 突然, it is seldom the word you want for a general 'sudden' event.
For plain 'suddenly, without warning' use 突然; 急 is the compact element inside everyday expressions; 急激 adds rapid, sharp change of degree; 不意 stresses being caught off guard; 「にわか」 covers things springing up on the spot.
Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only
Japanese equivalents
See also
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