expression
in an instant; in a flash; right away
Slang expression meaning something happens extremely quickly, as if in a second. Often used in casual speech and online communication.
そのゲーム、秒でクリアしたよ。
I beat that game in a flash.
彼の話はつまらなくて、秒で飽きた。
His story was so boring I got tired of it right away.