/ blaɪð; NAmE / adjective [ usually before noun ]
1.
( disapproving ) showing you do not care or are not anxious about what you are doing :
He drove with blithe disregard for the rules of the road.
2.
( literary ) happy; not anxious :
a blithe and carefree girl
► blithe·ly adverb :
He was blithely unaware of the trouble he'd caused.
'It'll be easy,' she said blithely.
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WORD ORIGIN
Old English blīthe , of Germanic origin; related to Dutch blijde , also to bliss .