lightning fast

idiomatic not-comparable

(idiomatic) Extremely fast, fast as lightning.

Japanese Meaning

極めて速い / 稲妻のように速い / 電光石火の

Her lightning fast reflexes saved the child from stepping into traffic.

彼女の稲妻のように速い反射神経のおかげで、その子は道路に飛び出さずに済んだ。

Sense（1）

(idiomatic) Extremely fast, fast as lightning.