An insouciant action or quality shows someone's lack of concern about something which they might be expected to take more seriously.
例句
Programme-makers seem irresponsibly insouciant about churning out violence.编程者似乎对大批量制造含暴力因素的产品处之漠然，毫无责任心。
英英词典释义
Adjective
1. marked by blithe unconcern;
"an ability to interest casual students""showed a casual disregard for cold weather""an utterly insouciant financial policy""an elegantly insouciant manner""drove his car with nonchalant abandon""was polite in a teasing nonchalant manner"