| heedless(adjective, violent, wild, fast, quick) |
| hell-for-leather(adjective, informal, fast) |
| hell for leather(expression, adjective, idiom) |
| high-speed(adjective, fast, quick, rapid, speedy) |
| immediate(adjective, prompt, fast, irritable, quick) |
| in nothing flat(expression, hot, fast, quick, speedy) |
| lively(prompt, fast, quick, speedy, brisk) |
| mad |
| mercurial(fast, quick, rapid, speedy, brisk) |
| nasty(bad, heavy, irritable, risky, dangerous) |
| negligent(adjective, wild, thoughtless, deed, irresponsible) |
| nippy(adjective, fast, rapid, swift, urgent) |
| on the double(expression, hot, fast, quick, speedy) |
| parlous(adjective, dangerous) |
| perilous |
| plunging(violent, fast, quick) |
| precipitant(violent, fast, quick, rash, reckless) |
| precipitous(adjective, sharp, fast, course, quick) |
| pronto(hot, fast, quick, rapid, nimble) |
| ready(prompt, hot, fast, quick, nimble) |