You use blithe to indicate that something is done casually, without serious or careful thought.
例句
It does so with blithe disregard for best scientific practice.没有考虑最科学的做法就轻率地这么做了。
ADJ-GRADED
无忧无虑的；快乐无忧的
Someone who is blithe is cheerful and has no serious problems.
例句
She said 'hi' with the blithe assurance of someone who knew how much she'd been missed.她高兴地说了声“嗨”，好像确信大家非常想念她似的。
英汉词典释义
adv.
欢乐地;快活地;无挂虑地
They blithely carried on chatting, ignoring the customers who were waiting to be served.他们继续开心地聊天,将等着购物的顾客们置于一边。He blithely ignored her protests and went on talking as if all were agreed between them.对她的抗议他毫不在意地拋诸脑后，只管继续往下说，仿彿他们之间什么都谈妥了似的。