Translation guide
Describes something happening extremely quickly, almost instantaneously. Japanese uses various adverbs, onomatopoeia, and set phrases to convey this sense of sudden speed.
To say that something happens immediately or in the blink of an eye.
Literally 'one moment'. Used as an adverb with で or に to mean 'in an instant'. Very common and natural.
To emphasize that something appears or changes so quickly it's almost like magic.
Onomatopoeic adverb suggesting a sudden, bright flash or quick action. Often used for lights, ideas, or quick movements.
To compare the speed to lightning or a flash of light.
A literary idiom meaning 'with lightning speed'. Used in formal or dramatic contexts.
電光石火のごとく走り去った。
He dashed away in a flash.
All three mean 'in a flash', but 一瞬 emphasizes the brevity of the moment itself, while あっという間に and 瞬く間に emphasize the subjective feeling that time passed quickly. あっという間に is more colloquial; 瞬く間に is slightly more formal or literary.
Do not translate 'in a flash' literally as フラッシュの中で. This would mean 'inside a camera flash' and is not idiomatic.
泥棒は一瞬で消えた。
The thief disappeared in a flash.
彼は一瞬で問題を解いた。
He solved the problem in a flash.
一瞬のうちに消えた。
It disappeared in a flash.
Literally 'in the time it takes to blink'. A very natural and common phrase for something happening in a flash.
瞬く間に準備が整った。
The preparations were done in a flash.
Means 'in the time it takes to say "ah"', i.e., before you know it. Very common in spoken Japanese.
あっという間に食べ終わった。
He finished eating in a flash.
An adverb meaning 'in no time', 'at once'. Slightly more literary or emphatic than すぐに.
たちまち人だかりができた。
A crowd gathered in a flash.
Means 'immediately' or 'right away'. While not as vivid as 'in a flash', it is the most common way to express quick action.
すぐに戻ります。
I'll be back in a flash.
パッと明かりがついた。
The light came on in a flash.
いいアイデアがパッと浮かんだ。
A good idea came to me in a flash.
Onomatopoeic adverb for a swift, smooth movement or change. Implies something done quickly and cleanly.
彼はさっと立ち上がった。
He stood up in a flash.
Literally 'like lightning'. Used in similes, more common in written or descriptive language.
稲妻のように素早く動いた。
He moved in a flash, like lightning.