あっけらかん

adverb taking the 'to' particle

unconcernedly; nonchalantly; as if nothing happened

Describes a carefree, untroubled attitude, often when one might be expected to show concern or embarrassment. Used with と or as an adverbial.

• 彼かれは失しっ敗ぱいしてもあっけらかんとしている。

  Even after failing, he acts as if nothing happened.

adverb taking the 'to' particle

blankly; vacantly; absentmindedly

Describes a dazed, empty expression or state, often after a shock or when one's mind is elsewhere.

• 突とつ然ぜんの知しらせに、彼かの女じょはあっけらかんと口くちを開あけたままだった。

  At the sudden news, she stood there blankly with her mouth open.