The quality of being alert or on the alert; briskness; nimbleness; activity. (noun)
Examples of word alertness
Unfortunately, the placebo takers also had unmistakable headaches and, temporarily, occasional decreases in alertness or energy.
The medium/high caffeine consumers who got the placebo reported a decrease in alertness and increased headache, neither of which were reported by those who received caffeine.
The undead we encountered were a nice exercise in alertness, because some of them were invisible, and as we fought our way through them up to the parapet where the questgiver waited for us, I admired our solid teamwork.
To take pleasure in one's own mental alertness is the worthiest, the wholesomest, and not the easiest manner of listening to music ....
And then in alertness, in understanding, what democracy means, their realizations, not in itself but the consequences of the vote, in that realization, giving those people an opportunity of carrying on the government of the country in a reasonably good way.
By implementing the technology in soldiers 'helmets, DARPA hopes to provide advantages to US troops by enhancing cognitive abilities; improving long-term alertness; and reducing stress, anxiety, and pain.
However, its ability to boost alertness is short-lived.
Brown (1931), Buttgereit (1932), Caldwell and Wellman (1926), Cox (1926), Dunkerley (1940), and Fauquier and Gilchrist (1942) found that leaders were characterized by alertness and keen awareness of their environment.
Besides, he displayed on several occasions serious lapses which call his alertness into questions.