sensitive; alert; aware; susceptible
quick-witted and agile; keen and nimble
sharp (eyes, ears, etc.); keen; acute; sharp-witted; shrewd; clever
quick; prompt; alert; smart; clever; astute
nervousness; oversensitivity
intelligence; discernment
quickness; agility; activity
quick to seize an opportunity
slowness; inertness; inability; lack of talent; dullness
nimble; agile; quick; quick (thinking); smart; alert
The Life and Strange Surprising Adventures of Robinson Crusoe (orig. Japanese title)
sharp (mind); keen; acute