Word family noun thought thoughtfulness ≠ thoughtlessness adjective thoughtful ≠ thoughtless adverb thoughtfully ≠ thoughtlessly
From Longman Dictionary of Contemporary Englishthoughtlessthought‧less /ˈθɔːtləs $ ˈθɒːt-/ ●○○ adjective UNKINDnot thinking about the needs and feelings of other people, especially because you are thinking about what you want OPP thoughtful a selfish and thoughtless manit is thoughtless of somebody to do something It was thoughtless of her not to tell you where she was going.► see thesaurus at unkind —thoughtlessly adverb —thoughtlessness noun [uncountable]Examples from the Corpus
thoughtless• Many years before that, man has thought of the animal as being stupid and thoughtless.• But in fact, competition between the two men to produce the first pulp led to hurried, thoughtless design.• That certainly wasn't the intent, and we're sorry for any hurt this thoughtless headline caused.• We have caused enough harm by our thoughtless, irresponsible, selfish behaviour.• It was thoughtless of Miguel to take the vehicle - but maybe he'd needed it in a hurry.• This thoughtless response is so much easier than confronting the real reasons, as it has an inevitability about it.• the thoughtless use of nuclear technologyit is thoughtless of somebody to do something• It was thoughtless of him to not send her flowers. 