/blaɪð/ adj.1.(heedless)+ disregard, indifference, ignorance不在意的；漫不经心的；+ confidence, optimism盲目的
It does so with blithe indifference to best scientific practice.这种做法是对最好的科学实践的漠视。
She said 'hi' with the blithe assurance of someone who knew how much she'd been missed.她说了声“嗨”, 语气中带着一种知道自己多么被思念的盲目自信。
2.<文>(cheerful)愉快的；快乐的；无忧无虑的
those blithe summer days when we were young我们年轻时那些快乐的夏日
a blithe spirit who would cheer any party在任何聚会上都能活跃气氛的无忧无虑的人