0 happily careless and not thinking about the results of your actions -- 嘻嘻哈哈的；大大咧咧的，满不在乎的
He's slaphappy in his approach to rules and regulations. 他视规章制度如儿戏。
That is slaphappy to the degree of irresponsibility.
They treat the patient in a sort of slaphappy way.
