[adj] without care or thought for others; "the thoughtless saying of a great princess on being informed that the people had no bread; `Let them eat cake'"
[adj] 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"
[adj] showing lack of careful thought; "the debate turned into thoughtless bickering"