Johnny on the spot

46 Moby Thesaurus words for "Johnny on the spot":
      advertent, agog, alert, all ears, all eyes, apt, assiduous,
      attentive, aware, careful, concentrated, conscious, decisive,
      diligent, earnest, expeditious, finical, finicking, finicky,
      heedful, immediate, instant, instantaneous, intense, intent,
      intentive, meticulous, mindful, nice, niggling, observant,
      observing, on the ball, on the job, open-eared, open-eyed,
      openmouthed, prompt, punctual, quick, ready, regardful, speedy,
      summary, swift, watchful