careless/ˋkɛrlIs; ˈkeələs/adj not giving enough thought and attention to something, so that you make mistakes, damage things etc [ careful ] 不小心的﹐粗心的: a careless mistake 粗心的错误be careless of sb It was careless of you to leave your keys in the car. 你太粗心大意了﹐把钥匙忘在车里。—carelessly adv —carelessness n [U]