The quality or state of being alert—staying aware, awake, and ready to notice or respond to something quickly.
From 'alert' plus the noun-forming suffix '-ness,' creating a word for the quality of being in a state of readiness and attention.
Animals like meerkats have incredible alertness—they take turns being lookouts for the group, and this cooperation strategy helped them survive in dangerous environments for thousands of years!
Complete word intelligence in one call. Free tier — 50 lookups/day.