1.
in an instant; instantaneously; in a flash
Happening in an extremely short amount of time, almost immediately. Emphasizes the speed at which something occurs.
瞬時に判断する。
To judge in an instant.
火は瞬時に建物全体に広がった。
The fire spread to the entire building in an instant.
AIが瞬時に大量のデータを処理する時代になった。
We have entered an era where AI processes vast amounts of data instantaneously.
Composed of 瞬 (blink/moment) + 時 (time) + に (adverbial particle). The base noun 瞬時 can also be used in other constructions: 瞬時の判断 (split-second judgment). Common collocations: 瞬時に判断する (judge instantly), 瞬時に反応する (react instantly), 瞬時に理解する (understand instantly). Similar expressions: 一瞬で (in a moment), たちまち (immediately).