hell-for-leather

adjective

Characterized by great celerity: breakneck, expeditious, fast, fleet, quick, rapid, speedy, swift. Idioms: quick as abunnywink. See fast/slow/velocity.

adverb

In a rapid way: apace, fast, posthaste, quick, quickly. Informal flat out, lickety-split, pronto. Idioms: full tilt, in a flash, in nothing flat, like a bat out of hell, like a blue streak, like a flash, like a house on fire, like a shot, like a streak, like greased lightning, like the wind, like wildfire. See fast/slow/velocity.