alertness
UK: əˈlɜːtnəs | US: əˈlɜːrtnəs
n. the state of being watchful and ready to respond quickly
n. mental sharpness or attentiveness
The word "alertness" derives from the Italian phrase "all'erta" (literally "on the height"), originally a military term for being on high ground to watch for danger. The root "alert" entered English in the 16th century via French ("alerte"), combining "à" (to) + "erte" (height, from Latin "erectus"). The suffix "-ness" (Old English "-nes") was later added to form the noun, abstracting the quality of being vigilant. This reflects a vivid progression from physical watchtower duty to generalized mental readiness.
The soldier's alertness prevented a surprise attack.
Drivers must maintain high alertness during night journeys.
Her academic success stems from remarkable intellectual alertness.
The meerkat's survival depends on constant alertness for predators.
Coffee can temporarily enhance mental alertness.