| whirlwind(adjective, fast, rapid, speedy, urgent) |
| wide-awake(adjective, sharp, bright, lively, alert) |
| strong(feeling, alive, existing, breathing) |
| crack(adjective, cool, smooth, smart, clean) |
| crafty(adjective, smart, cunning, shrewd, clever) |
| expeditiously(adverb, early, quickly, rapidly, soon) |
| feverish(adjective, hasty) |
| flashing(adjective, hot, rapid, speedy, sudden) |
| meteoric |
| nimble-witted(adjective, smart, bright, intelligent, clever) |
| nippy(adjective, fast, rapid, swift, urgent) |
| out of the blue(adjective, sudden) |
| pith(noun, place, body, cause, start) |
| receptive(adjective, sharp, smart, bright, sharp-witted) |
| responsive(adjective, understanding, keen, sharp, smart) |
| running(adjective, easy, articulate, confident, hasty) |
| rushing(adjective, violent, fast, abrupt, hasty) |
| sassy |
| savvy(adjective, understanding, smooth, keen, sharp) |
| scintillating(adjective, witty) |