in a flash

Prepositional phrase

idiomatic

(idiomatic) Instantaneously; very quickly; in almost no time.

Japanese Meaning

瞬時に / あっという間に / 極めて素早く

The magician disappeared in a flash, leaving the audience stunned.

その手品師は一瞬で姿を消し、観客を呆然とさせた。

Sense（1）

(idiomatic) Instantaneously; very quickly; in almost no time.

It happened so fast that it was all over in a flash.