Definitions

1. noun

The state of being awake and watchful; a state of being vigilant or attentive.

“She had a keen sense of alertness during the night shift.”

2. noun

The ability to notice and respond to things that are happening around you.

“The driver’s alertness helped him avoid the accident.”

3. noun

A state of being ready to react or take action quickly.

“The team’s alertness during the emergency response was impressive.”