lost in thought; showing preoccupation; "an absent stare"; "an absentminded professor"; "the scatty glancing quality of a hyperactive but unfocused intelligence"
not practical; not workable or not given to practical matters; "refloating the ship proved impractical because of the expense"; "he is intelligent but too impractical for commercial work"; "an impractical solution"
condition of heightened watchfulness or preparation for action; "bombers were put on alert during the crisis"
very attentive or observant; "an alert and responsive baby is a joy"; "caught by a couple of alert cops"; "alert enough to spot the opportunity when it came"; "constantly alert and vigilant, like a sentinel on duty"
(usually followed by `to') showing acute awareness; mentally perceptive; "alert to the problems"; "alive to what is going on"; "awake to the dangers of her situation"; "was now awake to the reality of his predicament"
not unconscious; especially having become conscious; "the patient is now awake and alert"
deeply absorbed in thought; "as distant and bemused as a professor listening to the prattling of his freshman class"; "lost in thought"; "a preoccupied frown"