lost in thought; showing preoccupation; "an absent stare"; "an absentminded professor"; "the scatty glancing quality of a hyperactive but unfocused intelligence"
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"
characterized by careless unconcern; "the heedless generosity and the spasmodic extravagance of persons used to large fortunes"- Edith Wharton; "reckless squandering of public funds"
marked by or paying little heed or attention; "We have always known that heedless self-interest was bad morals; we know now that it is bad economics"--Franklin D. Roosevelt; "heedless of danger"; "heedless of the child's crying"