| mercurial(adjective, sharp, lively, fast, restless) |
| observant(adjective, understanding, cool, keen, sharp) |
| precipitous(adjective, unusual, fast, rash, abrupt) |
| pronto(adjective, adverb, informal, hot, fast) |
| rapidly(adverb, early, quickly, instantly, speedily) |
| sharp-witted(adjective, keen, ability, smart, bright) |
| slapdash(adjective, casual, speedy, hasty, swift) |
| superficial(adjective, light, casual, slick, hasty) |
| warm(adjective, feeling, alive, existing, breathing) |
| zippy(adjective, sharp, energetic, lively, active) |
| accelerated(adjective, direct, express, prompt, hot) |
| alacritous(adjective, prompt, lively, fast, flexible) |
| animate(adjective, bright, energetic, lively, active) |
| ardent(adjective, energetic, lively, active, vigorous) |
| awake(adjective, understanding, cool, keen, sharp) |
| breathing(life, alive, existing) |
| breathless(adjective, hasty, urgent) |
| capable(adjective, smart, bright, intelligent, skilled) |
| center(noun, place, body, cause, start) |
| curt(adjective, fast, irritable, rapid, speedy) |