definition of
alertness

[1] #1 alertness n. [watchfulness, wakefulness, vigilance] the process of paying close and continuous attention; "wakefulness, watchfulness, and bellicosity make a good hunter"; "vigilance is especially susceptible to fatigue". wn

[2] #2 alertness n. [alerting] a state of readiness to respond; "alerting was indicated by the desynchronization of the EEG". wn

[3] #3 alertness n. [sharp-sightedness, on the qui vive] lively attentiveness. wn