irresponsible
adj
(of people, actions, etc) not showing a proper sense of responsibility (指人、 行为等)不负责任的, 没有责任感的
an irresponsible child 没有责任感的孩子* irresponsible behaviour 不负责任的行为
It is irresponsible of you not to prepare students for their exams. 你不帮助学生准备考 试就是不负责. Cf 参看 responsible 4.