in a flash

: rush, dash

: to break forth in or like a sudden flame or flare

: to appear suddenly

: a sudden burst of light

: a movement of a flag in signaling

: a sudden and often brilliant burst

: flashy, showy

: of, relating to, or characteristic of flashy people or things

: of, relating to, or characteristic of persons considered social outcasts

: by very brief exposure to an intense altering agent (such as heat or cold)