unconcern

Noun

Lack of interest or care; indifference or apathy. / Freedom from worry or apprehensiveness; insouciance or nonchalance.

Japanese Meaning

関心や気遣いの欠如、無関心・冷淡といった状態 / 心配事や不安から解放された、憂いのない穏やかな状態

What is this buttons?

His unconcern about the upcoming deadline frustrated the whole team.

Google Translation / DeepL Translation

彼の迫り来る締め切りに対する無関心がチーム全体を苛立たせた。

Details

Sense（1）

Lack of interest or care; indifference or apathy.

Elizabeth took up some needlework, and was sufficiently amused in attending to what passed between Darcy and his companion. The perpetual commendations of the lady, either on his handwriting, or on the evenness of his lines, or on the length of his letter, with the perfect unconcern with which her praises were received, formed a curious dialogue, and was exactly in union with her opinion of each.

Google Translation / DeepL Translation